How Many Amps For Water Heater?

How Many Amps Does A Water Heater Use? (Find Out Now!)

People have a tendency to forget about items in their homes that they have grown accustomed to.When something is effectively hidden, it is easy to forget about it.A water heater is one of those things.The only time we are aware of it being present is when the hot water is not operating properly.Whenever we receive our energy bill, we are aware that our appliances are the most expensive items on the statement.One query can have you scratching your head and pondering about the most neglected appliance.

  1. Can you tell me how many amps the water heater consumes?
  2. A basic electric water heater with a heating element rated at 4,500 watts consumes 18.8 amps.
  3. The usual electric water heater operates at 240 volts and requires a 30-amp circuit breaker to operate.
  4. Electric heaters that run on gas need 12 amps at 115 volts.

Electric Water Heater Amps

It is vital to understand the amps in order to avoid overloading the home’s electrical system. If this occurs, it will continue to trip the breaker in order to keep the home secure from harm. These are the variables that influence the amount of electricity consumed by the water heater.

  1. Heater Type
  2. Fuel Type
  3. Capacity
  4. Energy Efficiency

It is vital to understand how many amps the water heater consumes in order to properly operate it.There are a variety of possibilities when it comes to determining which water heater has the appropriate quantity of amps for the circuit breaker.Sifting through these four aspects can assist you in better understanding your alternatives and making an informed selection on the best one for you.

Tank Vs. Tankless Water Heater

Electric water heaters are available in two configurations: tank and tankless.A water heater with a tank continuously warms the water that is contained within the tank.Tankless water heaters, on the other hand, only heat water when it is required for immediate consumption.The traditional type of water heater has tanks, and they consume more energy than tankless water heaters.Even though a tankless electric water heater consumes more amps than a conventional water heater, it can help you save money on your energy bill.

40 Gallon Electric Water Heater

The most typical tank size in a home is 40 gallons in capacity.If the tank in an older home has to be replaced, the odds are strong that it will be the same size as the original.When a professional is sent out to remove an old unit, the majority of the time there is no payment for the service.A 30 amp circuit breaker is required for a 40-gallon electric water heater.Despite the fact that it will not consume the entire 30 amps, the machine must have adequate power to function properly.Because 30 amps is the most common amp rating for all appliances, there is no need to upgrade.

Tankless Water Heater Requirements

Tankless water heaters require 120 amps in order to function properly.It is significantly greater than the cost of water heaters with tanks.Older homes have electrical systems that are barely 100 to 200 amps, and they require an update from a licensed professional electrician.One option they will consider is expanding the number of circuit breakers available by installing a subpanel.This procedure will increase the amperage available to you, allowing you to utilize the tankless water heater in a safe manner.

Electric Vs. Gas

A water heater is a device that heats water by using electricity or natural gas. Depending on the type of fuel used to operate the water heater, a difference in the quantity of power consumed can be observed. Every month, we’ll take a look at the different types of gasoline and how much it costs to go to work.

Electric Water Heaters

The cost of an electric water heater is less expensive than a gas water heater.The monthly price to keep it operating, on the other hand, will be more expensive than natural gas.In most cases, the typical monthly expenditure for an electric water heater is around $42.When it comes to installation, it is far less expensive than a gas unit.Connection to an electrical system is less difficult than connection to a gas line.When dealing with electricity or natural gas, it is advisable to leave the installation to the specialists unless you are certified.

  1. 240 Volt circuit is required for an electric water heater with a tank.
  2. The water heater must have its own dedicated 30 amp breakers.
  3. Aside from this circuit, no other appliances or electrical equipment should be connected to it.
  4. In some cases, an electrical upgrade may be required prior to the installation of the system.
  5. A tankless water heater necessitates the use of a 120 amp circuit breaker.

Older homes may require an upgrade, or they may trip a breaker or require a reset to function properly.In order to assess the cost, the technician should provide an estimate.

Gas Water Heaters

The cost of a gas unit is 25 to 50 percent more than the cost of an electric unit. When it comes to your overall payments, it is the monthly cost that will save you money. The cost of running a gas water heater on natural gas is around $30 per month. The cost of installation is determined by these considerations.

  1. If the gas line has previously been installed
  2. If an upgrade is necessary, this will be shown.
  3. The labor costs incurred by each firm that was contacted

A gas water heater with a tank requires 30 amps of electricity.Because this is the most typical configuration, most houses will not require an update.Older homes have 100 to 200 amp service, which is more than enough to serve the needs of the entire neighborhood.A 120 amp circuit breaker is required for a tankless gas unit.Older homes will need to have their electrical systems upgraded in order to accommodate this device.

Changing Fuel Types

The most common argument for choosing natural gas water heaters is because natural gas is less expensive than electricity.Some people wish to switch from natural gas to electricity because they are uncomfortable around natural gas lines.However, the good news is that you may easily convert from one format to another.Asking a professional and receiving an estimate are the most effective methods of determining this.The majority of businesses provide free consultations.Several companies may offer you a fantastic bargain if they know you are serious about making the transition.

  1. If you have electricity and would like gas, you should check with your local gas supplier to determine if they service your region before making the purchase.
  2. If the provider provides service to the area, they may be able to provide an estimate without physically visiting the place.
  3. When you contact your local gas provider, you should ask them the questions listed above.
  1. Is the gasoline type you’re looking for available in the area?
  2. What is the approximate cost of installing a gas line?
  3. Is it necessary to get permissions in order to install a gas line and water heater?
  4. Is it required to enhance the overall amperage capacity?
  5. Approximately how much would a typical monthly gas bill be?

Obtaining the answers to these questions will enable you to make an informed judgment about your situation. If you are beginning from scratch, it is expected to be pricey; nonetheless, take into consideration the savings.


In addition to the right amperage and circuits, the capacity is an important consideration.If the capacity cannot meet the demand, it makes no difference whether the system is powered by gas, electricity, or a tank.The water heater’s capacity must be sufficient to meet the needs of the entire family.The amount of power consumed is determined by the capacity of the unit.Tanks, for example, are available in capacities ranging from 20 to 80 gallons.The larger the tank, the longer it will take to heat up and the greater the amount of power that will be consumed.

  1. Starting with a 40-gallon tank is the most accurate approach to determine how much of a tank is required.
  2. A 40-gallon tank will provide enough water for a family of up to three people.
  3. Then, for each person in the house, add 10 liters of water.

Tankless Water Heater Capacity Calculations

Water heaters with coils are rated based on the flow rate, which is measured in gallons per minute.The higher the flow rate, the greater the amount of money that will be spent on utilities.Calculating the flow rate of each appliance will need them to be operated concurrently, and then adding them all together.Running a load of laundry while also taking a shower and running the dishwasher is an example of multitasking.It will be necessary to combine the flow rates of each of them together.You may then multiply that number by the sizes of the tankless water heater systems to get a more accurate estimate of the cost.

  1. Calculating the capacity can give you a better sense of which one would work best for your situation.

Energy Efficiency Options Save Electricity

It has been proven via studies and research that water heaters account for 18 percent of total kilowatts consumed.It is important to get the most energy-efficient equipment possible in order to save money on your electric bill.Natural gas outperforms electricity in terms of efficiency.Home Team that has been upgraded We are a group of enthusiastic homeowners, home improvement professionals, and do-it-yourself enthusiasts who appreciate discussing home renovation, housekeeping, decorating, and other related information with other homeowners!What you’re searching for is here, whether it’s a step-by-step tutorial on how to fix an appliance or an estimate for the cost of erecting a fence.

How many amps does an electric hot water heater use?

Asked in the following category: General The most recent update was made on June 30, 2020.A water heater of this sort must be treated as a continuous load, which means that the branch circuit must be estimated at 125 percent of the heater’s rated ampacity in order to be considered safe.4500/240 = 18.75 amps can be run on a 20 amp OCPD, however 18.75*125 percent = 23.4 amps necessitates a 25 or 30 amp circuit, depending on the manufacturer.Electric water heaters necessitate the installation of a 240-volt dedicated circuit that serves only the water heater and none of the other appliances or devices on the circuit.In most cases, the circuit wiring will consist of a 30-amp double-pole breaker and 10-2 non-metallic (NM) or multi-conductor (MC) cable.In a similar vein, what size circuit breaker do I require for a 40 gallon electric water heater?

  1. It takes 4500 watts to power a typical household 30 or 40 gallon water heater, which is connected to a 30 A circuit breaker.
  2. In addition, how many amps does a 50 gallon electric water heater consume?
  3. The elements in the 50 gallon water heater *could* be just 3500 watts, in which case you would have 3500 / 240 = 14.6 amps on a 240-volt circuit, which is within 16 amps of the 80 percent rating of both a 12 AWG copper circuit with a 20-amp rating and the 20-amp rated circuit breaker.
  4. I’m wondering how many amps a 6 gallon hot water heater consumes.
  5. Amps: 16.7 Amps

How Many Amps Does A Water Heater Use? Compared By Type & Size

You must be aware of the amount of electricity consumed by your water heater. If you don’t know what I’m talking about, you should read the remainder of this tutorial. The amount of electricity to direct where and an estimation of the effectiveness of your appliance will be taught to you by us. The following is the answer to the question ″how many amps does a water heater use?″

Factors That Affect How Many Amps A Water Heater Uses 

AMP is an abbreviation for ″ampere,″ which is the standard unit of measurement used in the measurement of electricity.An amp is a unit of electrical current that is one hundredth of a volt.For the purpose of determining the amperage draw, the number of watts is divided by the number of volts passing through the outlet..When evaluating the power requirements for a water heater, you’ll need to understand what an amp is.

Heater Type (Tank Or Tankless)

Water heaters are available in two configurations: with a tank and without a tank.A tank-style water heater retains heated water, but a tankless water heater heats water on demand as it passes through the pipes.Because they only operate when there is no more water in the tank, the storage option consumes less amps.When you utilize hot water from a tankless heater, the system consumes just the amps that are required.This indicates that the system delivers a range of amperage values.If you consume a lot of water, your daily amp consumption will increase.


The larger the tank, the greater the amount of energy required to heat the water, as the water is being heated by a greater volume.Water storage tanks are available in capacities ranging from 20 to 80 gallons.Consequently, it is not always necessary to purchase the largest tank available.It is possible that your residence does not have enough amps to run the unit efficiently.Here’s our guide to finding the correct tankless water heater size for your situation.


  • The wattage of your equipment has a significant influence on the quantity of electricity it consumes. As the amount of watts required increases, so does the amount of amp power required. When it comes to electric water heaters, the normal amperage is 18.8 amps at 240 volts and 4500 watts.
  • A gas water heater, on the other hand, will consume the following fuels: 115 volts
  • less than 12 amps
  • less than 12 amps

Energy Efficiency  

A gas water heater, on the other hand, will consume the following fuel types: 115 volts, less than 12 amps; less than 12 amps

How Watts & Amps Are Calculated: What Breaker Do I Need? 

When determining the amperage, you must first determine how many watts are being used by the water heater.Here is the equation that you may use to solve the problem: P (W) equals I (A) multiplied by V (V) In order to discover how many amps are contained within a watt, you can use the calculation above.Let’s use the voltage of 120 volts as an example.You want to connect it to the power source where the volts come in first.P (watts) = 1 amp * 120 volts = 120 watts In this equation, one amp is equal to 120 watts, as demonstrated by the example.To figure out what size circuit breaker to use for a 30 gallon water heater, you’ll need to know how many watts it consumes.

  1. On average, these systems consume 25 amps at 120 volts, which equates to around 3000 watts.

Average Amperage Used by Residential Electric Water Heaters  

An electric water heater’s normal amperage is 18.8 amps at 240 volts and 4500 watts, and it operates at 240 volts.Using a gas water heater, you’ll consume a little less energy than that.″Can I use a 40 amp breaker to power a water heater?″ is a question that many people have.It is advised that you utilize a 30 amp double-pole breaker for this appliance if it will not be linked to any other objects in your home.The majority of the time, you’ll want to utilize a 30 amp circuit.It is necessary to replace the breaker if the water heater demands more than 30 amps.

  1. A circuit rated at 30 amps can only handle a maximum of 30 amps of power.
  2. If the temperature rises over this level, the wires will get hot and may become damaged.
  3. You want to make sure that the quantity of amps that are passing through your system is doing so in a safe manner.
  4. A 40 amp breaker is preferable for water heaters that have a greater power draw.
  5. The system will not trip until the electrical flow reaches a value greater than 40.
See also:  How To Turn Off Electric Water Heater
Hot Water Type   Tank Size   Watts Breaker Size (Amps)  
Electric 30 Gallon  3500w  30 amp 
Electric 40 Gallon  4500w  30 amp 
Electric 50 Gallon  4500w  30 amp 
Electric  80 Gallon  16,000w  30 amp 
Tankless Electric   n/a  28,000w  120 amp 

How Many Amps Do RV Water Heaters Use?  

A water heater for an RV consumes very little power.It is entirely viable to run the system on a 2 amp direct current battery.If you’re solely using electricity, you’ll likely need more amps—perhaps as much as 15 or 16.It is preferable to utilize gas since you can get away with merely running the electricity for a short period of time to get the igniter ignited.Once you’ve completed this, the system will simply and efficiently heat water with minimal effort.The greatest tankless water heaters for recreational vehicles may be discovered in this guide.

How Many Amps Do Tankless Water Heaters Use? 

Tankless water heaters use significantly more energy to heat water than traditional water heaters with a tank system in place.They require at least 120 amps to function on average, which consumes the majority of the electrical capacity of a home.Due to the increased need for these tankless water heaters, it is possible that you may need to upgrade your home’s electrical infrastructure in order to meet the increased demand.

People Also Ask (FAQs)

Does a water heater need a dedicated circuit?  

Water heaters, for the most part, require their own circuits. Because they tend to take a large amount of electricity at one time to heat water—particularly the tankless options—this is true for both tankless and traditional water heaters.

What wire do I use for a 30-amp breaker?  

For a 30 amp breaker, you’ll need a wire with a diameter of 10 gauge. The circuit breaker can only accept one type of size, which ensures that your electrical system is properly protected.

Can I replace a 3500-watt water heater with a 4500 watt?  

You won’t be able to do so without improving your electrical work. You can swap out a higher wattage for a lower wattage in the same spot, but not the other way around. Consequently, while you could replace the 4500 with a 3500 wattage device, you would not be able to replace the 3500 with another 4500 wattage one.


In short, you want to make sure that you are aware with the wattage and amp consumption of your water tank. As a result, you may be confident that you are using your home’s electrical systems effectively and properly.

How Many Amps Does Water Heater Use?

  • It is likely that the water heater in your home is one of the most vital but least thought about pieces of equipment in your residence. When shopping for a new water heater, one factor to consider is the amount of electricity the new unit would consume. The amperage is critical in ensuring that you do not overload the electrical system of your present house. The normal amperage for an electric water heater is 18.8 amps at 240 volts and 4500 watts, according to the manufacturer. With 115Volts, the typical use of a gas water heater is less than 12 Amps (US and Canada). However, the actual amount of amperage that a heater consumes is dependent on a variety of factors, including: Heater type, fuel type, capacity, and energy efficiency are all important considerations.

It is critical for every homeowner to be aware of the quantity of amps required by their water heater. Making a decision on a water heater may be a difficult undertaking, especially with so many options available. In any case, after you have gained an understanding of the numerous possibilities discussed below, you will be able to make an educated selection.

Heater Type: Tank or Tankless

It is possible to use a water heater in one of two ways: with a tank that holds water that is continually heated or with coils that heat water as needed.Tank heaters are often referred to as storage heaters or container heaters.These pieces of equipment are the oldest and most conventional types of equipment available.Tankless heaters are also referred to as on-demand heaters in some circles.These units have a more recent design.

Storage water heaters, on average, consume less electricity than tankless water heaters. However, because they are continually heating the water within their tank, they may consume more electricity in total than other types of appliances. Given the tankless heaters only operate when necessary, their overall power consumption may be reduced, depending on the amount of actual use they get.

What Size Breaker for a 40-Gallon Electric Water Heater?

Among home container heaters, a 40-gallon tank is the most often seen size.As a result, if you are installing this size unit in an older home, it is likely that you will be replacing a unit of comparable size.An old unit will have to be removed and replaced with a new one if an installation decides to use an older unit.In most cases, there is no additional charge.This size unit will often require a 30-amp circuit breaker, which is one of the most common sizes of circuit breakers found in residential buildings.Most homes will not require any form of electrical system update as a result of the installation of this type of gadget because of this.

How Many Amps Does a Tankless Water Heater Use?

On average, an on-demand heater consumes 120 amps of electricity to operate, which is significantly greater than the consumption of typical heaters, which consume just 30 amps.Many older homes only have 100 to 200 amps of available power, necessitating the installation of a professional electrician to improve the electrical system.During this upgrade, an electrician may recommend that you have a subpanel of circuit breakers installed in your home in order to improve the overall amount of amperage that is available.

Fuel Type: Electric or Gas

The type of fuel that your water heater burns has an impact on the quantity of electricity it requires to function properly. A water heater will often be powered by electricity or natural gas to operate.

Electric Water Heaters

These sorts of units are less expensive to purchase than gas-powered units, but they are more expensive to operate.This is due to the fact that electricity is generally more expensive than natural gas on a per-unit basis.The energy consumption of an electric water heater is around $42 per month on average.However, because it may be connected to your home’s electrical system rather than requiring the installation of a gas line, this sort of heater is typically less difficult to install.

How Many Amps Does an Electric Water Heater Use?

An electric heater with a tank necessitates the installation of a 240-volt dedicated circuit with a 30-amp fuse.The fact that this type of equipment requires a dedicated circuit means that an electrical update for your home could be required.A 120-amp circuit breaker is required for a tankless electric unit.When installing this sort of gadget in an older home, the electrical system will need to be upgraded.When it comes to on-demand water heaters, this improvement represents still another additional price in terms of up-front fees.

Gas Water Heaters

Heaters that run on gas are typically 25 to 50 percent more expensive than heaters that run on electricity, according to industry standards.However, because they are less expensive to operate, they are more likely to make up for the price difference over the long term.For the ordinary household, a gas water heater will cost around $30 per month on average.Due to the fact that gas units must be connected to a gas line, there may be an additional cost associated with installing such a device for the first time.This is especially true if you need to install a new natural gas line or improve your existing natural gas system to meet your needs.

How Many Amps Does a Gas Water Heater Use?

It will take 30 amps of electricity to power a gas water heater with a tank, which normally does not necessitate any changes to the home’s electrical system–even in older homes with just a total of 100 or 200 amps of service.A tankless device that works on gas will necessitate the use of a 120-amp circuit breaker.Because of the high amperage of this type of breaker, many older homes will require electrical system upgrades in order to support this sort of device.

Should You Change Your Heater’s Fuel Type?

  • Depending on who you ask, many people believe that if they currently have an electric water heater, it is difficult to switch to a gas one, or that the opposite is true. This isn’t always the case, of course. If you are interested in altering the sort of equipment you now have, all you need to do is consult with an expert. A large number of electricians and plumbers provide free consultations. Find a company in your neighborhood that performs this and just ask them to conduct an evaluation for you. Whether you’re thinking about switching to natural gas, you may check with your local gas supplier to see if they provide service in your region. Some carriers may even be able to offer you with an estimate of the expenses over the phone, if you ask nicely. When considering changing the fuel source for your water heater, ask yourself the following questions: Is the fuel type accessible in your area?
  • How much will the installation cost?
  • Will the installation necessitate the acquisition of a permit?
  • Does this new fuel type require you to update your home’s total amperage? How much will your monthly payment be for this new fuel type?

Once you have answered the questions above, you will be able to determine whether or not changing the fuel type of your heater is worth the time, effort, and money required. Changing the fuel type of your heater may necessitate more effort and expense during the installation process, but it may be more cost effective in the long run.


It is only when you have hot water when you need it that a water heater is truly beneficial.Regardless of whether the unit has a tank or not, or whether it is powered by gas or electricity, if it is not the proper size for your household’s water needs, it will not function properly.It is also dependent on the capacity of your heater as to how much power it will demand from it.Storage water heaters, for example, come in a variety of tank sizes ranging from 20 to 80 gallons.The larger the tank, the greater the amount of energy required to heat the water.A 40-gallon tank is normally suitable for a family of two to three people.

  1. You should increase the size of your water tank by 10 gallons for each new person that lives in your house.
  2. The capacity of on-demand heaters is measured in gallons per minute (or flow rate) and is expressed as a percentage.
  3. Your electricity or natural gas utility bill will rise in direct proportion to the amount of power the device consumes at any one moment.
  4. In order to calculate the flow rate that you will require for your house, you must sum the flow rate requirements of each of the fixtures that you want to operate at the same time together.
  5. To put it another way, if you want to be able to take a shower while also doing laundry and running the dishwasher, you must add the flow rates of each of these machines together.

Then you’d pick a tankless heater with a larger flow rate than the one you predicted….Using the Tankless Water Heater Sizing Diagram, you may determine which size heater will be most suitable for your needs.When it comes to heater capacity, it is critical that you strike a balance between the demands of your home and the electrical capacity of your heater.It may seem enticing to get a unit with the highest capacity available, but doing so may demand more amps than your home is capable of providing.

Energy Efficiency

According to studies, heating a home’s water accounts for around 18 percent of the overall energy consumed by the residence.The efficiency with which your heater utilizes energy will also have an impact on the number of amps the device consumes.Generally speaking, the more energy-efficient a heater is, the more amps it will require to operate.However, even if a more energy efficient heater may take more amperage to turn on, the unit will be in use for a shorter period of time, resulting in a reduction in total energy expenditures.A piece of equipment that is more than a decade old is often less energy efficient.In the event that your unit is more than 10 years old, it may be time for you to consider upgrading to a more energy-efficient model.

  1. Electric water heaters have a greater energy efficiency rating than gas water heaters, on average.
  2. However, because natural gas is often less expensive than electricity, the two units are typically equal in terms of cost.
  3. Keep an eye out for the Energy Star badge while shopping for a new heater.
  4. This mark indicates that the device complies with the Energy Star requirements.
  5. These gadgets have a tendency to be more energy efficient, which results in their being more cost effective.


Having access to hot water when you need it is no more a luxury, but rather a need in today’s day and age.As a result, you must locate a unit that is within your budget, both in terms of up-front fees and ongoing operating expenses.It is also critical to evaluate the total quantity of energy that your water heater will use from your home in order to verify that your electrical system is capable of handling the demand.

How Many Amps Does a Water Heater Use?

As an Amazon Associate, this website receives a commission on eligible sales made via it.For further information, please see this page.Knowing how many amps a water heater consumes is critical if you want to save money on your energy bills.This article concentrates on electric water heaters since they are the most popular type of water heater used in households; however, the formulae may be applied to a variety of other types and designs as well.A 4000 watt water heater operating at 120V consumes around 33.3 amps.Using an average of three hours each day, a water heater will consume 49.8 amps on a 120-volt circuit.

Water Heater Amp Size Guide

Here is a table showing the most common water heater watt capabilities and how many amps they consume, in case you don’t want to perform any calculations.The same water heater will draw varying amps depending on the voltage, as you can see in the diagram.According on the heater wattage, voltage, and running time, the amps drawn will vary.These power consumption figures are provided just as a point of reference.Because of variations in manufacturing design, the amount of water used by your water heater may vary.In order to find out how much electricity your water heater consumes, go to the owner’s handbook that was included with your purchase.

  1. The capacity of water heaters is also measured in gallons.
  2. The sizes recommended in the following table are based on the number of people who will be using it.
  3. The majority of these water heaters have at least 4000 watts of power, with some of the bigger models reaching 5000 watts or higher.
  4. As you can see, a 4000 watt water heater will require 416 amps per hour in order to run off of a 12V battery, which is quite a bit.
  5. It will take a pair of Mighty Max 250ah batteries to complete the task.

An additional battery bank is required if the heater is to be operated for more than an hour at a time.These are just for the sake of reference.The capacity of a water heater will differ based on its design.For further information, please refer to the owner’s handbook that comes with your device..Please keep in mind that these size suggestions are just intended to serve as broad guides.Water use varies widely not just from family to household but also from individual to individual, thus take into consideration your particular water consumption when determining what gallon is reasonable.

The most accurate approach to determine this is to keep track of how much water each member of your household consumes.Your electricity statement will give you an estimate of the entire amount of energy you have consumed.It is simple to determine the size of the water heater that will be required using this information.

Water Heater Amp Calculation Guide

Water heaters are available in a variety of forms, sizes, and designs.As well, use ranges from 10 minutes per day to more than 5 hours per day, therefore you must take into consideration your unique requirements when using these estimates.The formula for calculating this is as follows: Watts of the water heater divided by voltage equals amps drawn If you have a 4500 watt water heater that is connected to a 240V alternating current outlet, it will use 18.75 amps per hour.4500 divided by 240 is 18.75 As a result, the 4500 watt water heater consumes 18.75 amps from its power supply.Of course, this is only applicable if you use the heater for an hour at a time.If the gadget is used for three hours, multiply the amps by three to get the total power consumed.

  1. 18.75 multiplied by three is 56.25 amps Furthermore, if you only use the water heater for a short period of time (less than an hour), the calculations are uncomplicated.
  2. The equivalent of 18.75 amps per hour is 9.3 amps for 30 minutes, thus 10 minutes would be around 5 amps in total.
  3. In addition to water heaters, this method may be used to circular saws, coffee makers, microwaves, and other appliances and devices with variable runtimes.

Can a 240V Water Heater Run on 120V?

Yes, most 240V water heaters may be operated on a 120V power source.The owner’s handbook will provide information on whether or not your vehicle may be towed.Even if it is possible, the amps that are pulled will be different.Let us use the same example as before, a heater with a 4500-watt capacity.The heater consumes 18.75 amps per hour when operating on a 240V system.However, if you were to connect it to a 120V AC outlet, the power consumption would be: 4500 / 120 = 37.5 A 4500 watt water heater consumes 37.5 amps per hour when connected to a 120V system.

  1. The greater the voltage power, the lesser the amount of current drawn is likewise.
  2. Some of these heaters can also be operated at 110 volts, although the amp draw will be larger, despite the fact that the difference between a 110V and a 120V system will be far smaller.

What Inverter Size Do I Need For a Water Heater?

An inverter may be used to power a water heater as well as a variety of other appliances such as a television, refrigerator, kettle, and other items.In order for this to operate, you will need a substantial amount of battery capacity.In addition, a 4000 watt water heater need the availability of 5000 watts of inverter electricity.Assuming you have a 5000 watt inverter ready to go for the water heater, the next issue is: how many batteries will you need to power the water heater?If a 4500 watt water heater consumes 18.75 amps at 240V and 37.5 amps at 120V, the same figure on a 24V inverter system would be: 4500 / 24 = 187.5 amps.In the case of a three-hour duration, that is 187.5 amps each hour, or 562.5 amps total.

  1. To summarize, a 200ah battery will operate a water heater for an hour and a 600ah battery will run a water heater for three hours.
  2. Keep in mind that using the water heater for an hour will entirely deplete the 200ah battery’s capacity.
  3. This is not recommended since deep cycle batteries need to be recharged at a rate of 50 percent or higher.
  4. As a result, only 100ah of the whole 200ah capacity should be utilized.
  5. It is possible to lower the duration of the water heater to 30 minutes or increase the capacity of the battery bank from 200ah to 400ah.

If you need to operate the battery for three hours, you’ll need a battery bank with a capacity of 1000 amp-hours only for the water heater.If you use 12V batteries, the requirements are much greater, since they are twice as high as those for 24V batteries.In order to raise the voltage, it is possible to link additional 12V batteries together in series.The idea is that a huge inverter and battery bank are required for a water heater to function properly.Instead of using it just for a water heater, you can currently use it to power a variety of other appliances using these rechargeable batteries.If you have a solar system that is connected to the power grid, the heater can be powered by electricity.

However, if you are off the grid, a smaller water heater or alternative power source, such as a generator, may be the best option for you.

How Many Solar Panels Do I Need to Run a Water Heater?

It is feasible to utilize solar panels in conjunction with a water heater, yes.In order to do so, you will need a huge solar array, in addition to either a battery bank or some type of backup power source.A 4000 watt water heater will require at least 4500 watts of solar electricity, which is equivalent to 12 x 350 watt solar panels.These will occupy a total area of around 210 square feet of floor space.Because there are 5 hours of sunlight each day, there should be enough electricity to keep the heater running throughout the day.The array has the potential to produce 4000 to 4200 watts per hour under optimal weather conditions.

  1. The greater the number of daylight hours, the longer you can keep the heater running.
  2. These estimates also include the assumption that the heater will be running for at least an hour.
  3. If the heater is not in use for as long as possible, the amount of solar power required will be significantly reduced.
  4. If you have a roof or a lot of ground area, it is possible, but is it a wise investment?
  5. A refrigerator, air conditioner, and other appliances may be powered by a solar array with a capacity of 4000 watts.

You will not be able to run any of those appliances with a 4000 watt water heater.The second disadvantage is that you will be unable to use the heater if it rains or if the sky becomes overcast.It will be necessary to have a battery bank in order to power the water heater in any conditions.As previously demonstrated in the calculations, a number of huge batteries are required to power the whole system.If you want to put it another way, you will need a 4000 watt solar panel, an inverter capable of converting it to 5000 watts, and a battery bank capable of storing 500Ah to 1000Ah only for the water heater.As a result of these considerations, a smaller water heater or a solar water heater is preferable for an off-grid setup.

Are Solar Water Heaters Worth It?

It is preferable to utilize a solar water heater rather than operating water heaters off of solar panels as an option.This should not be mistaken with ordinary electric water heaters that are powered by solar panels or batteries, since they are designed only for the purpose of water heating.Solar water heaters are similar in appearance to solar panels and are mounted on roofs.Built-built collectors attract sunlight into the heater, where it is transformed into energy, which is then utilized to heat the water in the system.These gadgets can only be used to heat water and cannot be used to provide energy to any other appliances or devices.There are two types of solar water heaters: electric and solar thermal.

  1. Active solar water heaters are equipped with a system that distributes the hot water around the home.
  2. An active direct system transfers hot water to showers and faucets by a direct connection.
  3. In an indirect system, the collectors heat the water by transferring heat through a heat transfer fluid.
  4. Water is heated by convection in passive solar water heaters, which do not have built-in pumps to accomplish the heating.
  5. The water in some of the units is stored in an inbuilt collector storage container, which is heated by the sun.

In a thermosyphon system, water is heated by metallic plates, which are then conveyed from the valves to the faucets through the system.Passive solar water heaters are less expensive than active solar water heaters since they do not require the installation of sophisticated mechanisms, yet active systems are more efficient.In either case, they are more convenient to operate than a traditional water heater and consume less energy.


The wonderful thing about water heaters is that they are long-lasting, and you should only need to purchase one, which should last for several years. You will not have any problems running your water heater from alternating current, batteries, or a solar panel once you get the calculations figured out. Alternatively, as demonstrated, you may use a solar water heater to heat your water.

How many amps does a 50 gallon water heater use?

A typical 50-gallon electrical water heater consumes 4500 watts of electrical power. A current of 18.75 amps in a 240-volt electrical circuit is equivalent to 4500 watts.

How many amps does a 220 scorching water heater use?

In most cases, an electrical water heater requires 18.8 Amps @ 240 Volts and 4500 Watts to function properly.

How many amps is a 30 gallon water heater?

The department circuit must be estimated at 125 percent of the rated ampacity for the kind of water heater that would be considered a stable load, according to the manufacturer’s specifications. If you want to work on a 20 Amp OCPD, you’ll need a circuit that can handle 25 or 30 Amps.

What dimension breaker do you want for a 50 gallon electrical water heater?

For water heater circuits, the standard configuration is 10 conductors with a floor (10/2) and a 30 amp circuit breaker for the water heater.

What dimension breaker do I want for a 240-volt water heater?

Electrical water heaters necessitate the installation of a 240-volt dedicated circuit that serves only the water heater and no other appliances or devices in the home. The circuit wiring may include a 30-amp double-pole breaker as well as 10-2 non-metallic (NM) or multi-conductor (MC) cable.

Can I exploit a 40 amp breaker for water heater?

It is not possible to use a 40A breaker on a 10 wire. If you’re confident that there are (at the very least)8 wires running all the way from the breaker to the water heater, you may simply swap the 30A breaker for a 40A breaker, but only after you’ve confirmed the size of the wires running throughout the whole circuit, as described above.

How many amps does an electrical water heater draw?

The majority of electrical water heaters operate at 240 volts and 18.8 amps, with a heating factor of 4,500 watts. A gasoline water heater consumes far less electricity, drawing just around 12 amps at 115 volts. The standard home container heater has a 40-gallon tank and is powered by a 30-amp circuit breaker, according to the manufacturer.

Why does my water heater maintain tripping the breaker?

Breaker Breaker Breaker Breaker Breaker Breaker The following are three possible causes for why a burning water heater may trip the breaker; there may be water leaking on the circuit breaker, a problem with the unit’s thermostat, or a problem with the breaker. The most common source of the problem is a defective thermostat. As a result, the thermostat should be changed in this instance.

How many amps does a 4500 watt factor draw?

Specifically, the answer to this question is the exact figure obtained by converting 4500 watts to amps: 18.75 volts.

What dimension breaker do I want for my water heater?

Calculate the size of the circuit breaker you’ll need for the heater by multiplying the value of present by a factor of 125 percent. A 1500-watt heater on a 120-volt circuit necessitates the use of a 15.6-amp circuit breaker. In order to avoid the possibility that a 15-amp breaker is insufficient, you should go for a 20-amp breaker, which has the best possible score.

How do I do know what amp my water heater is?

For the reason that you already know the wattage and voltage of your water heater, all you need to do now is follow the Ampere formula, which is I (amps) = P (watts)/V. (volts). If I have a three-thousand-watt heater tank that requires 120-volt electricity, for example. You must divide your watts by the number of volts in order to obtain its amperage.

What dimension breaker do I want for a 20 gallon electrical water heater?

Electrical water heaters require a dedicated 240-volt dedicated 30-amp circuit as well as a 10-2 nonmetallic (NM) or multiconductor (MC) cable to function properly. This means that the breaker only provides electricity to the water heater and not to any other household appliances. A 30-amp circuit breaker can supply power to all 4500watt water heaters, regardless of their gallon capacity.

How many heaters are you able to run on a 30 amp breaker?

The number of heaters you’ll be able to connect to at least one thermostat is also determined by the circuit and wire configuration you choose.

Volts Measurement of breaker Most watts on circuit
240 20 Amp Double Pole 3840
240 30 Amp Double Pole 5760

How many amps does a 7500 watt heater draw?

How many heaters are you able to run on a 20 amp circuit?

A 20-amp breaker can assist any combination of heaters with a combined output of up to 3,840 watts. For example, with a single thermostat, the breaker may be able to support two 1500-watt heaters or three 1000-watt heaters simultaneously.

How many watts can 20 amps deal with?

A 20-amp, 120-volt circuit produces 2,400 watts at 20 amps x 120 volts.

How many amps does a heater use?

A 1500-watt home heater operating at its highest setting will consume 12.5 Amps. A circuit breaker will trip when the 15 Amp limit is surpassed by a number of lights or a television that are connected to the circuit at the same time.

What dimension breaker do I want for a 1000 watt heater?

(For example, two 1000W and one 1500W 240V heaters add up to 3500 Watts total. If all three heaters were to be connected to the same circuit, they would each require 12/2 wire and a 20 Amp 2-Pole breaker, which would be rather expensive. If more heaters are required, either a new circuit must be installed or the wire and breaker dimensions must be increased to suit the load.)

Is a double 20 amp breaker 40 amps?

Nope. It suggests that two 20 A breakers are ganged together in order to protect a circuit that is protected by two burning wires. Tripping both breakers at the same time at 20 A will trip both breakers at the same time to prevent a security situation in which live voltage can be detected in the machine after one breaker has been tripped.

How do I do know if I’ve 15 or 20 amps?

Can I exchange a 15 amp breaker with a 20 amp breaker?

The answer is that it is possible, but it is not recommended without first consulting with an electrician to assess the situation. Simply because a 15-amp breaker trips, you should not immediately upgrade to a 20-amp breaker to fix the problem. Any other manner, you run the risk of causing an electrical fire to engulf your house.

Does a double breaker imply 240 volts?

According to the answer: It is possible, but not recommended, to do so without first consulting with an electrician about the situation. Simply because a 15-amp breaker trips, you should not immediately upgrade to a 20-amp breaker. Any other manner, you run the risk of causing an electrical fire to engulf your property.

Does a double 15 amp breaker equal 30 amps?

Yes, as a result of the breaker attracting 30 amps from each leg of the circuit breaker… There is one leg for every busbar. Due to the fact that a double breaker includes a connecting bar and either side will travel if both legs travel, it may be preferable to use two individual 30 amp breakers.

Water Heater Amps

Making sure that your water heater has the appropriate amperage avoids your home’s electrical system from getting overwhelmed.Get bids from as many as three professionals!Enter your zip code below to get matched with top-rated professionals in your area.Because there are so many various types of water heaters on the market, it can be difficult to determine how many amps your water heater requires.Your home’s electrical system might soon become overwhelmed if you don’t have enough amperage available.Breakers that frequently trip without warning or water that takes a long time to heat might be signals that you need to upgrade your electrical system’s capability to manage your water heater.

  1. If you’re thinking about upgrading your water heater, there are a few things to consider when determining how many amps your new water heater will require.

What is the Standard Amperage for an Electric Water Heater?

The majority of electric water heaters operate at 240 volts and 18.8 amps, with a heating element rated at 4,500 watts.A gas water heater consumes less amps than an electric water heater—about 12 amps at 115 volts.The standard home container heater has a 40-gallon tank and is powered by a 30-amp circuit breaker, according to the manufacturer.The actual amount of amperage consumed by water heaters varies across models and is dependent on important factors such as the kind of water heater being used, the type of fuel required, and the capacity of the water heater.

Water Heater Types: Tank vs Tankless

Goffkein may be found at heaters are classified into two categories: tank and tankless.The most common type of tank water heater, also known as a storage or container heater, has tanks that physically retain water and heat it on a continuous basis.Coils are built into tankless water heaters, and they heat the water on demand while you’re using it.While tankless water heaters often consume more energy and draw more current than their tank counterparts, they consume less power throughout their lifespan since they only operate when water is required.For a typical 40-gallon tank water heater, you’ll need a 30-amp breaker to power it.

  1. Due to the fact that this breaker size is relatively common, it is unlikely that you will need to improve your electrical system in order to manage the appropriate amount of electricity when installing a tank of this size.
  2. On average, a tankless water heater consumes 120 amps of electricity to operate.
  3. If your property is older, you’ll almost certainly require the services of a professional electrician to improve your system and increase the amount of amperage accessible in your home, among other things.

Fuel Type: Electric vs Gas Water Heaters

  • A 240-volt circuit with a 30-amp breaker is required to power an electric water heater (with a tank). a 120-amp circuit breaker is required for a tankless electric water heater
  • a gas water heater with a tank requires 30 amps, but a tankless gas water heater necessitates the use of a 120-amp circuit breaker.

Water heaters can be powered by electricity or natural gas, depending on the model.Electric water heaters are often less expensive than gas water heaters, however the expense of maintaining an electric water heater is higher.For a new electric water heater, whether it is a tank or a tankless one, you will almost certainly need to modify your electrical system.Gas water heaters are directly connected to a gas line, which means that they are often more expensive to install at the outset of the project.In contrast, unless you live in a very old home with limited power capabilities, you will almost never have to alter your electrical system to accommodate a natural gas water heater.

Other Factors That Influence Water Heater Amperage

Water Heater Capacity

Because the tank size varies, the overall quantity of power consumed by your water heater is determined by its capacity.Larger tanks will necessitate the use of more power in order to heat all of the water contained inside them.A 50- to 60-gallon storage tank is sufficient for a single person or a small family (no more than three people), but a medium-sized 80-gallon tank can accommodate three to four persons comfortably.In general, you should increase the size of your tank by 10 gallons for every additional person that lives in your home.Tankless water heater capacity is measured in gallons per minute, or flow rate, and is determined by the amount of water that it can deliver.The higher the flow rate, the greater the amount of power required by your system.

  1. For example, if you want to run the dishwasher while also doing a load of laundry and taking a hot shower at the same time, you will most likely need to improve your electrical system to accommodate your demands.

Energy Efficiency

The energy efficiency of certain units is higher than that of others.The energy efficiency of electric water heaters is generally superior to the energy efficiency of natural gas water heaters.Generally speaking, tankless water heaters are more energy efficient than traditional tank-type water heaters.Additionally, energy-efficient machines that do not operate continuously, as well as newer ones, will consume fewer amps.The energy efficiency of your water heater is likely to be lower than that of newer models if it’s more than a decade old.Consider replacing your old one with a new one to lower your power use, or you will ultimately need to improve your electrical system to fit your new one.

What Size Breaker for a Hot Water Heater: A Breaker Size Solution

Is your electrical water heater tripping the breaker on a regular basis?Is it possible that your heater overheated without you noticing?You have clearly indicated that you are experiencing difficulties in matching your appliance with its safety device based on just a few questions.What size breaker do you recommend for a hot water heater, I hear you ask?For the most part, 30-amps is the common size for heaters.It is important to note that this breaker ampacity does not necessarily work for every water heater available.

  1. There is a formula for determining the proper breaker size, but there are other important aspects to consider, which we will discuss later in this article.

Understanding Your Water Heater

When purchasing an electric water heater, one of the most common mistakes made by homeowners is failing to verify the amperage rating of the unit.Some heater tanks are just labeled with the voltage and wattage requirements, but not with the ampacity requirements.It is preferable if you obtain your tank specs from the shop or the brand manufacturer directly themselves.The size of your heater must serve as the foundation for establishing the appropriate breaker size.The following are the three criteria you should examine in order to assure your safety: Voltage- The volts provided by your boiler are critical to the operation of a properly functioning circuit.Depending on the size of your tank and the power of your heater, you can connect it to a 220 or 240 Volt outlet.

  1. Wattage- Include the wattage requirements for your heater in your list.
  2. Knowing the wattage of your gadget is extremely beneficial if your equipment often consumes a large amount of power due to its tank size and other features.
  3. It will assist you in your quest for a proper breaker to manage the situation.
  4. Wire Size- Finally, it is critical to understand which cable type is suitable with the breaker size of your hot water heater system.
  5. An mismatched size or broken cables that have been reused might put your heater and breaker at greater risk than they are worth.

A Breaker Size Solution: What’s the Formula?

If you’re unsure of the amp size you’ll need, doing a simple calculation will provide the answers you need.Knowing the wattage and voltage of your water heater already, all you have to do is follow the Ampere formula, which is I (amps) = P (watts)/V (voltage) (volts).As an example, I have a 3,000-watt heater tank that requires 120-volt power to operate.You must divide your watts by the number of volts in order to obtain its amperage.Solution: P/V = I = P/V I is equal to 3000 watts x 120 volts.I equals 25 amps.

  1. You could be thinking that a gadget with a current of 25 amps necessitates the use of a breaker with the same capacity.
  2. After all, it is at this point when overloading and over-tripping begin to occur.
  3. The National Electric Code (NEC) stipulates that you must maintain a continuous load of 125 percent of the maximum continuous load at all times.
  4. In order to acquire the safe amount for your electric water heater breaker size, you must first complete this step.
  5. Applying the continuous load rule to the previous example, we get 31.25 amps: 125 percent x 25 amps = 31.25 amps.

If this is the case, you can purchase the nearest amp size, which is 35 amps.The Square D by Schneider Electric HOM235CP is a highly recommended device for a 35-amp circuit breaker.If you have a 20-amp breaker devoted to your 25-amp water heater, you should anticipate the heater to trip the breaker on a regular basis.Allowing enough room for your breaker will allow a power surge to occur without triggering the breaker.Check out this video from House Wiring get a better understanding of how to properly size your water heater wires and breakers!

– Video on YouTube

What Size Breaker for 40 and 80-Gallon Water Heater?

Most households utilize a water heater with a tank capacity ranging from 40 to 80 gallons, depending on how much they rely on warm water on a daily basis.You’ll need their wattage and voltage to figure out how many amps breaker for water heater of these tank sizes you’ll require, and then you’ll use the answer from earlier.The typical capacity of a 40-gallon heater is 4500 Watts at 240 Volts, according to the manufacturer.Using the formula I = P/V once more, 4500W/240V Equals 18.75 amps.Then, taking into account the continuous load (125 percent x 18.75A), we’ll arrive at a total of 23.4 amps.According to our response, a 40-gallon water heater requires at the very least a 25-amp breaker, which is the closest match to the amperage amount.

  1. However, I strongly advise utilizing 30-amp breakers because they are a more secure breaker size.
  2. For example, an 80-gallon heater fueled by 5500 watts and 240 volts will result in 5500W/240V x (1.25 continuous load) = 28.64 amps while operating at 5500W/240V.
  3. This means that a 30-amp dedicated circuit breaker is sufficient.
  4. Pro-tip: Although a 30A breaker appears to be insufficient for an 80G tank, putting a 40A breaker will not safeguard the device in the event of an overloaded circuit.
  5. A breaker amperage that is far higher than necessary will not trip when it is required.

What’s the Correct Wire Size for a Water Heater?

  • If the wiring between a water heater and its breaker is mismatched, the connection will not function properly. Check that the amperage of your heater corresponds to the size of the wires on it. You can use the following list as a guide: 20-amp heaters require 12-gauge cable
  • 25-amp heaters require 10-gauge wire
  • 30/40-amp heaters require 8-gauge wire
  • and other big heaters up to 50-amps require 6-gauge wire.

Also, evaluate the size of your water heater’s circuit breaker. Circuit breakers rated at 30 amps, which are often used for big boiler tanks, require a 10-2 nonmetallic or MC cable. It is appropriate for starting loads up to 40 amps and a steady load up to 35 amps with this type of wire.

Preventive Measures Before Buying a Circuit Breaker

When selecting the appropriate water heater circuit breaker size, it is important to be mindful of the amp differential between the breaker and the water heater.It’s critical that you obtain the correct size.A breaker that is either too large or too little might result in an electrical hazard.If your circuit breaker is too tiny for the amperage needs of your water heater, you should anticipate your CB to trip on a regular basis.Not only that, but too much switching on and off of the heater might result in internal damage to the device.It is not recommended that your water heater share a circuit with other appliances, and you should consider upgrading the circuit breaker if necessary.

  1. A breaker that is capable of handling a larger amperage than designed does not always imply that it is safer for the heater.
  2. If the tank experiences a sudden short circuit or overload, your circuit breaker will ignore the occurrence, providing no protection at all.


Choosing the appropriate size circuit breaker for a hot water heater is not that difficult if you obtain the necessary information.You can determine the right breaker size simply by studying the three wire heater factors — voltage, wattage, and wire size — and how they interact.A basic calculation would also suffice, but keep the breaker size as close as possible to the quantity of your response (the actual amp size of the heater).A 30-amp circuit breaker is commonly used for an electrical water heater, thus a circuit breaker such as the Q230 30-Amp Double Pole Type QP Circuit Breaker will be suitable for the job.

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