Solved! How to Select the Right Water Heater Size
Image courtesy of istockphoto.com Q: Our water heater is nearing the end of its useful life. I’ve turned up the temperature on the tank to its highest level, but the water that comes out of the faucet is no longer hot at all. It is therefore necessary to purchase a new water heater. Our present tank has a 30-gallon capacity, which was plenty when we purchased the property ten years ago. However, our family has expanded, and we are now consuming more water for bathing and laundry than before. What type of water heater do I require?
And you’re absolutely correct: Increased people in the family means more water consumption.
“The output is more or less fixed,” he adds.
For a tank-style heater, household size is a simple indicator of hot water needs.
Based on the number of people living in the residence, you may estimate the required tank capacity (in gallons) as follows:
- For one or two people, 23 to 36 gallons are needed, for two to four people, 36 to 46 gallons are needed, and for three to five people, 46 to 56 gallons are needed
- For five or more people, more than 56 gallons are needed (add 10 gallons for each extra person).
A 40-gallon water heater, such as A. O. Smith’s ProLine Power Vent Gas Water Heater (available from SupplyHouse), should be sufficient for the average household of four. However, it should not be your only factor to consider. It is possible to obtain a more realistic picture of your family’s hot water requirements by delving a bit further.
In addition to tank capacity, consider a water heater’s first hour rating.
When a tank is fully heated, the first hour rating (FHR) specifies how much hot water it can generate in a single hour when fully heated. At peak consumption, this statistic indicates the appliance’s efficiency (how rapidly the water heater can reheat the water) and provides an indication of how much water it can manage in a given amount of time. A 50-gallon ProLine Power Vent Water Heater (available fromSupplyHouse) has an FHR of 90 gallons, which means it can supply up to 90 gallons of hot water in an hour, as an illustration.
Make use of the statistics in the table below to help you predict peak hour use and establish the best FHR for your situation.
- Bathing or showering (per person) requires 20 gallons
- Washing hair (per person) requires 6 gallons
- Washing hands (per person) requires 2 gallons
- Washing dishes by hand requires 6 gallons
- Shaving requires 3 gallons
- Running the dishwasher requires 14 gallons
- Running the clothes washer requires 30 gallons.
Consult with a professional Find qualified plumbing professionals in your area and receive free, no-obligation estimates for your plumbing project on HomeAdvisor. +Image courtesy of supplyhouse.com
If a larger tank won’t fit in the existing space, consider a tankless heater.
Tankless heaters, which are often wall-mounted, are able to fit into smaller spaces since they do not require a large storage tank, as O’Brian points out. Typical tank water heaters may be up to six feet tall and 22 inches in diameter, with a capacity of 50 gallons. An alternative tankless water heater with equivalent power, for example, the Takagi Tankless Natural Gas Water Heater (available from SupplyHouse), is just 20 inches high, 14 inches wide, and less than 10 inches deep, making it an ideal choice for small spaces.
If you have a limited amount of available space, a tankless water heater may be the best option. Image courtesy of istockphoto.com
To select the right tankless water heater, estimate the necessary flow rate based on hot water usage and the required change in temperature.
Tankless water heaters do not have a storage tank to hold hot water. Instead, they heat it only when it is required. “Flow rate is the most important factor to consider when sizing a tankless water heater,” O’Brian explains. The following information will assist you in estimating the flow rate requirements for your family.
- To begin, figure out how much hot water you use during peak hours. Peak consumption is defined as the period of time during which you consume the largest amount of hot water. In order to compute the maximum amount of hot water you would consume at one time, consider the following list of typical flow rates (per fixture) in gallons-per-minute (gpm)
- Water flow rates for sink faucet: 1 gpm
- Bathtub: 3 gpm
- Shower: 2.5 gpm
- Dishwasher: 3 gpm
- Clothes washer: 3 gpm
- You’ll need a tankless water heater with a minimum flow rate of 5.5 gpm if, for example, your peak consumption comes after dinner when you’re running the dishwasher and having a shower at the same time (three gallons per minute plus two and a half gallons per minute). Next, find out what the temperature of the water is that is entering your home. Simply turn on a cold water faucet and allow it to flow for a couple of minutes before measuring the temperature of the cold water using a thermometer. To calculate the needed temperature rise, subtract the cold water temperature from 110 degrees Fahrenheit (the typical home hot water temperature) and multiply the result by 100. For example, if the cold water temperature is 65 degrees Fahrenheit, the water heater will need to heat the water 45 degrees Fahrenheit in order to reach 110 degrees Fahrenheit, resulting in a temperature rise of 45 degrees Fahrenheit being required. Increase the flow rate by the amount of temperature rise that is necessary. As O’Brian points out, “all units should be equipped with a chart that depicts the flow of hot water at various temperature increases.” For example, the Takagi T-D2-IN Natural Gas Tankless Water Heater (available fromSupplyHouse) has a maximum flow rate of 10 gpm, with the emphasis on the word “maximum” in the name of clarity. The Takagi has an efficient flow rate of 10 gpm in a warm area where just a temperature increase of 20 degrees is required. Alternatively, if you require the water heater to raise the temperature of the water by 45 degrees Fahrenheit, the flow rate drops to around 7 gpm, as stated on the flow rate chart given by the manufacturer.
Check out this video from SupplyHouse on how to properly size tankless water heaters for a more visual explanation. It is with great pleasure that SupplyHouse.com brings you this article. BobVila.com is the source of the information and viewpoints presented. Consult with a professional Identify qualified plumbing professionals in your area and receive free, no-obligation quotes for your plumbing project.+
What Size Water Heater Do I Need?
That is an excellent question. What is the solution? It is necessary to determine how much hot water you use on a regular basis during your busiest “hot-water-using” hour in order to receive an accurate response. However, if you simply want a rough estimate of the size you require (as opposed to a precise calculation), follow these guidelines:
- 30-40 gallons for one to two people
- 40-50 gallons for two to three people
- 50-60 gallons for three to four people
- 60-80 gallons for five or more people
We’ll explain why the numbers in the table above are only “rough estimates” and why they may not be precise enough to satisfy your hot water requirements. We’ll also demonstrate how to calculate the precise water heater size that will fulfill your requirements (and saves you money). Please be advised that this essay will focus on the size of tank water heaters. Interested in a tankless water heater but not sure what size to get? Check out our blog on tankless water heater sizes for some guidance.
Simply get in touch with us and we’ll take care of everything.
Only need a loose estimate for now? Start here…
Homeowners may simply require a general understanding of water heater dimensions in order to obtain a better sense of how much their water heater installation will cost in order to budget accordingly. Prediction: the size of your water heater has a direct relationship with the cost of running it; the “larger” your water heater, the more expensive it is to run it. Depending on how many people live in your household, you may estimate the size of the dumpster you’ll need (see below). Please keep in mind that the values in this table are intended to be used as very broad guides only, and they may not exactly reflect your hot water requirements.
As you can see, the size of the tank you require is entirely dependent on your hot water use patterns.
In contrast, if you only seldom use more than one hot water device at the same time, you may only want a considerably smaller tank. That being stated, before purchasing a water heater, you should be certain that the tank capacity is appropriate for your needs. The reason behind this is as follows:
- Inadequate hot water due to a water heater that is too small may result in never having enough hot water, and/or a water heater that is overworked, resulting in frequent repairs or early collapse. A water heater that is overly large may result in higher-than-necessary energy expenditures (since it is heating water that is not being used)
Are you ready to find out what size water heater you require? Take a look at this.
Want to know the exact size water heater you need? Do this.
To figure out what size water heater your home need, you must first figure out how much water is used during “peak hour demand.” In the context of hot water, peak hour demand refers to the amount of hot water you require (measured in gallons) during the busiest hour of your normal day. Keep in mind that showers, out of all hot water activities/appliances, are the ones that consume the most hot water. That being said, if everyone in your home showers in the mornings on a regular basis, your “peak hour” is most likely to occur around this period.
2. Use the chart below to add up the gallons of hot water you need during this hour.
You should consider all of the hot water activities that you would ordinarily fit into that specific hour once you’ve identified which hour is your busiest hour. To determine your approximate peak hour usage for electricity, utilize the chart below. Source
3. Find a water heater that has a “first hour rating” within 1-2 gallons of your peak hour demand.
Every water heater is equipped with an FHR (first hour rating). Using a full tank of hot water as a starting point, this number represents the amount of gallons of hot water the unit can supply in a single hour of operation. So, in general, if your FHR and peak hour demand are in sync, your water heater will provide enough hot water to suit your demands. If you are on a manufacturer’s website, you may discover the FHR of a water heater in the “specifications,” “features,” or “performance” sections of the water heater (see below).
It will be referred to as the “Capacity (first hour rating)” in the report.
Need help from a Florida plumber?
Simply get in touch with us. Upon request, we will provide you with a free estimate in which we will determine the precise tank size you require. We’ve been providing high-quality water heater installations in Florida for more than 50 years, and every one of them is guaranteed by our 100 percent satisfaction guarantee! View a map of our service area in Florida.
- Should I Repair or Replace My Water Heater
- Should I Repair or Replace My Water Heater
- Should I Replace My Water Heater There are three things to keep in mind:
Sizing Guide: What Size Water Heater Do I Need for My Home?
When it comes to water heaters, the typical lifespan varies depending on the sort of system you have. However, the kind of water available in your location will have an influence on the performance of your water heater system. A conventional gas water heater is designed to last between 8 and 12 years, depending on how well it is maintained. An electric water heater, on the other hand, is meant to have a life cycle of 10 to 15 years, depending on the manufacturer. Your water heater may need to be replaced if it is leaking or making loud noises.
It’s crucial to become familiar with the different water heater sizes available before making a decision on which system to purchase.
Water Heater Sizes
What size water heater do you require to meet the needs of your household? If you have a large number of children, the answer to this question will be different for each one. For example, a household of three to four people should acquire a water heater that holds 50 to 60 gallons. A home of 5 to 7 people, on the other hand, may require a water heater with a 60 to 80 gallon water tank. An 80 gallon water heater will offer you with adequate hot water to shower, do laundry, and wash dishes if you live alone with your spouse.
These are approximate measurements for your residence. The size of your water heater will be determined by a variety of factors, including the number of people in your household and the length of time you spend in the shower on average.
Hot Water Usage Habits
The procedure of determining the appropriate size for a water heater will vary from family to family. If a family of 5–7 people lives in a 60–80 gallon water heater, for example, this may not be necessary. If you have a household of this size, a 50–60 gallon water heater may be sufficient for your needs in some instances. In addition, a water heater with a water tank that is bigger than 30 gallons may be required for a household of two people. It is dependent on your water use patterns that the size of your water heater will be determined.
- The process of determining the appropriate size of a water heater for your home is quite crucial.
- As an added bonus, a water heater that is too small for your household will have to work harder to keep up with your demands.
- Alternatively, a water heater that is too large for your home may result in a rise in the overall cost of your energy bills.
- Continue reading:How Big of a Condensing Furnace Do I Need?
How to Determine How Much Water You Use
While the estimations provided above can be used to get an approximate idea of the amount of water heater you will want, there is a more exact technique of determining the size of a water heater. First and foremost, you must examine your water use patterns in order to estimate your peak water consumption hour. If your family showers from 8:00 a.m. to 9:00 a.m. every morning, this is the time of day when you use the most water. You’ll need to figure out how many gallons of water you use throughout this period of the day to be accurate.
- If there are a total of 5 people in your household who shower in the morning, you should multiply 10 gallons by the total number of water usage sessions, which is 5.
- This means that a family of five would consume 50 gallons of water each morning from 8:00 a.m.
- However, it is probable that you will consume more than 50 gallons of water to wash the dishes from your meal.
- Your total water use will be equivalent to 56 gallons once you have finished washing your dishes, assuming that each member of your household takes a shower.
- 63 gallons of water have been consumed by your family after everyone has done bathing, cleaning dishes, and doing laundry.
- The First Hour Rating (FHR) of a water heater should be more than the entire volume of water consumed during your highest water usage hour, which you should look for while comparing different water heater sizes at the store while shopping.
- This rating may be obtained on the website of the manufacturer.
It will be situated at the top of this sticker on your water heater, and it will read “FHR Rating.” More information may be found at: Reasons Why It’s Critical to Replace Your Lead Pipes
Other Factors to Consider While Sizing Water Heaters
The size of your water heater may be increased if one or more persons in your household choose to take a bath in the morning instead of showering. A basic little bathtub has a capacity of 40 gallons of water on average, which is plenty for most people. A huge bathtub, on the other hand, may be able to accommodate up to 140 gallons of water. We propose that you have your children reuse the same bathwater in order to save money on your water costs. If you choose to acquire a tankless water heater rather than a typical water tank, you will be required to follow a new set of rules when determining the appropriate size for your water heater.
- The Flow Rate and Temperature Rise should be calculated in order to establish the size of the tankless water heater that you will require.
- Giant gallons are used to measure the entire volume of water.
- If you want assistance in determining the appropriate size water heater for your home, please contact our staff at (484) 206-8594.
- Additionally, we offer a variety of other services such as water line installation, air conditioning tune-ups, furnace repairs, and drain cleaning, among others.
- Since 1977, we’ve been offering trustworthy plumbing, heating, and air conditioning services to people of the Commonwealth of Pennsylvania.
Sizing a New Water Heater
A correctly sized water heater will satisfy the hot water requirements of your family while also functioning more effectively. As a result, when choosing a water heater, be certain that it is the appropriate size. These are the guidelines for sizing these systems, which you can find here:
- Water heaters that are tankless or demand-type
- Solar water heating systems
- Storage and heat pump (with tank) water heaters
- And other options.
Consult a trained contractor for assistance in sizing combined water and space heating systems, which may include certain heat pump systems, as well as tankless coil and indirect water heaters. If you haven’t already decided on the sort of water heater that would be most appropriate for your house, read on to learn more about choosing a new water heater.
Sizing Tankless or Demand-Type Water Heaters
When rating tankless or demand-type water heaters, the greatest temperature rise that may be achieved at a given flow rate is taken into consideration. For this reason, in order to calculate the appropriate size of a demand water heater for your home, you must first estimate the flow rate and temperature increase that will be required for its application (either the entire house or a distant use, such as a bathroom). To begin, make a note of the number of hot water gadgets you anticipate using at any given moment.
- This is the intended flow rate that you’ll need for the demand water heater that you’ve purchased.
- You may estimate the flow rate by holding a pan or bucket under the faucet or shower head for a minute and measuring the flow rate that way.
- (or liters per minute).
- Installing low-flow water fixtures can help to lower flow rates.
- Assume that the entering water temperature is 50 degrees Fahrenheit (10 degrees Celsius) unless you know differently.
- Water should be heated to 120 degrees Fahrenheit (49 degrees Celsius) for the majority of applications.
- For dishwashers without internal heaters and other similar uses, you may wish to heat your water to 140 degrees Fahrenheit (60 degrees Celsius).
- When the water temperature reaches 140 degrees Fahrenheit, use caution since it raises the risk of scorching.
- At a flow rate of 5 gallons per minute through gas-fired demand water heaters and 2 gallons per minute through electric demand water heaters, a temperature rise of 70 degrees Fahrenheit (39 degrees Celsius) is often achieved.
Some tankless water heaters are thermostatically regulated, which means that they may adjust their output temperature based on the amount of water flowing through them and the temperature of the water entering them.
Sizing a Solar Water Heating System
Basic system sizing entails calculating the total collector area and storage capacity required to satisfy 90 percent to 100 percent of your household’s hot water demands throughout the summer. Solar system contractors utilize spreadsheets and computer programs to assist them assess the size of their systems and the number of collectors they need.
Contractors often adhere to a guideline of around 20 square feet (2 square meters) of collector space for each of the first two family members, with the third family member receiving an additional 20 square feet (2 square meters). If you reside in the Sun Belt region of the United States, you should add 8 square feet (0.7 square meters) to your living space for every extra person; if you live in the northern United States, you should add 12–14 square feet.
A modest storage tank (50- to 60-gallon capacity) is normally suitable for one to two individuals, although a larger tank may be required. It is sufficient for three to four persons to use an 80-gallon storage tank of medium size. A big tank can accommodate four to six people comfortably. Active systems have a solar storage tank that grows in size in proportion to the size of the collector – generally 1.5 gallons per square foot of collector for active systems. When the demand for hot water is minimal, this helps to keep the system from overheating and breaking down.
Another set of calculations required in estimating your solar water heating system is analyzing the solar resource available on your construction site, as well as establishing the optimal orientation and tilt of the solar collector. For further information on these calculations, please see thesolar water heaterspage.
Sizing Storage and Heat Pump (with Tank) Water Heaters
You should use the water heater’s first hour rating to determine the correct size for your home – this includes heat pump water heaters with tanks. The first hour rating indicates the amount of gallons of hot water that the heater can provide per hour of operation (starting with a tank full of hot water). The tank capacity, heat source (burner or element), and size of the burner or element are all factors to consider. The first hour rating is labeled as “Capacity (first hour rating)” in the upper left corner of the EnergyGuide label, which is displayed on the screen.
The first hour rating may also be found in product literature provided by the manufacturer.
To estimate your peak hour demand, do the following:
- Determine what time of day (morning, noon, or evening) you use the most hot water in your house and record that information. It’s important to consider the amount of people that will be living in your house. Making an estimate of your maximum hot water use during this one-hour time of the day—also known as your peak hour demand—can be done using the worksheet below. Please keep in mind that the spreadsheet does not estimate total daily hot water use.
The worksheet example displays a total demand of 66 gallons during peak hour usage.
As a result, this home would require a water heater with a first-hour capacity of 66 gallons or greater.
|Use||Average gallons of hot water per usage||Times used during 1 hour||Gallons used in 1 hour|
|Shaving (.05 gallon per minute)||2||×||=|
|Hand dishwashing or food prep (2 gallons per minute)||3||×||=|
|Total Peak Hour Demand||=|
|1 hand dishwashing||3||×||1||=||3|
|Peak Hour Demand||=||66|
*Estimates are based on averages derived from a variety of information published on the internet, including government sources. Various calculators are available on some water heater manufacturer websites, which are depending on the duration of the use case and other criteria.
What Size Water Heater Do I Need?
A water heater is a necessary investment for any home, regardless of its size. Having said that, it’s critical to ensure that you get one that is the appropriate size in order to fulfill the demands of your family. Otherwise, you may find yourself without hot water for your morning shower on a more frequent basis than you would want. Today, we’ll go over the differences between the two most common types of water heaters in order to assist you in selecting the best one for your needs. We’ll also provide you an overview of the most common water heater sizes, as well as guidance on how to select the most appropriate size for your needs.
Storage Tank or Tankless?
Storage tank water heaters and tankless water heaters are the two most common types of water heaters. You must first select whatever sort of water heater you intend to purchase before determining the appropriate size.
A tankless water heater, despite the fact that it is more expensive up front, will ensure that you always have hot water. Tankless water heaters function by heating water on demand using built-in coils, which means you’ll always have hot water on hand when you need it. As a result, these types of water heaters are more energy efficient than typical storage tank water heaters, which may result in a reduction in your monthly energy expenditures. The only snag is that there is a catch. They are only capable of producing a limited volume of hot water every minute.
This allows you to take many showers at the same time!
- Per minute, only a limited amount of hot water is available
- Not suitable for all people
- High initial outlay of funds
Tank-style water heaters are significantly more widespread than tankless water heaters. This type of water heater is distinguished by the presence of an insulated tank that reserves hot water until it is required. We’ve all had the unpleasant experience of running out of hot water or having to wait for the water to heat up before getting into the shower. These sorts of events occur because storage tank units have a recovery increase, which refers to the quantity of water they can heat in an hour, which causes them to overheat.
- Hot water that is available for a limited length of time
- Not as energy-efficient as before
Water Heater Sizes
There are many different sizes of hot water heaters available, and you must first assess your usual water use in order to make an informed decision on which size to purchase. Several important considerations should be kept in mind in order to further limit down your search:
- Natural gas, liquid propane, or electricity as a fuel source: Which will you choose? Is it possible that your water heater will connect to your boiler? Making this determination initially will assist you in narrowing down your selections and making the purchasing experience much simpler
- Physical dimensions- Make certain that the water heater you choose will fit into the area you have allotted in your home. Residence Size- Do you live in a little condo or in an enormous house? Is it simply you and your spouse, or do you have a large number of relatives and friends? When buying for a water heater, the size and occupancy of your family are two of the most critical considerations to make since you don’t want the person who showers last to be stranded with cold water.
When compared to a small condo where you only need hot water for one task at a time, you’ll most likely need a larger capacity water heater to accommodate a household where multiple people shower, run the dishwasher, wash dishes with the faucet, and do laundry at the same time, as opposed to a large family home.
What Size Water Heater Do I Need?
For those of you who are considering a storage tank water heater, the following is a general reference to the storage tank capacity:
- In order to accommodate 1 – 2 people, you’ll need a water tank with a minimum capacity of 30 gallons. A tank with a capacity of at least 40 gallons is required for 2 – 3 persons. You’ll need at least a 50-gallon capacity tank (electric) or a 40-gallon capacity tank (natural gas or liquid propane) if you’re cooking for 3 – 4 people. If your household has five or more members, you’ll need an 80-gallon electric tank or a 50-gallon natural gas or liquid propane tank.
Tank for storing items Hot water heaters are scaled based on the amount of BTUs they use and the amount of water they hold in gallons. Again, the more the amount of time you rely on hot water on a daily basis, the greater the amount of BTUs and capacity you will require. Consider, for example, how many showers individuals in your home take as a result of the consequences of their actions. If you have four individuals each take a ten-minute shower over the course of an hour, you will consume around 40 gallons of hot water in total.
- It only takes one person to take a longer shower for the tank to be completely empty.
- If you’re thinking about taking the tankless way, your purchasing experience will be a little different.
- You must, however, keep the following two considerations in mind: The pace of flow and the temperature rise.
- In order to calculate the required temperature rise, subtract the entering water temperature from the desired exiting water temperature and multiply the result by 100.
- Before making a purchase choice, conduct some investigation and testing to determine the temperature of your ground water.
- In this scenario, a tankless water heater with a temperature increase of 50 degrees Fahrenheit would be appropriate.
- You’ll need at least 3.5 GPM if you’re running 1 or 2 fixtures at the same time. If you want to run two or three fixtures at the same time, you’ll need at least 5 GPM. If you want to run three or four fixtures at the same time, you’ll need at least seven GPM. If you want to utilize five or more fixtures at the same time, you may require additional tankless units to be installed in succession.
Making a Decision
We hope that this information has assisted you in better understanding the many elements and sizes to consider when selecting a new water heater. Total Home Supply has a wide variety of water heaters, including both storage tank and tankless models, all of which are eligible for free shipment to anywhere in the contiguous United States. If you require any extra assistance before to making your purchase, please do not hesitate to contact us. Our in-house specialists would be pleased to assist you in selecting the most appropriate unit for your water heating requirements.
What Size Water Heater Do I Need?
Please keep in mind that this content may contain affiliate links. This means that, at no additional cost to you, we may gain a small profit on purchases made via our links. Tankless water heaters are becoming increasingly popular (particularly in bigger houses), but traditional tank devices are still far more widespread and are not likely to become obsolete any time in the near future.
So, how can you choose which one is the greatest match for you? It’s a straightforward process. Simply begin with the fundamentals.
What is the Capacity of a Water Heater Measured In?
First and foremost, let’s get this over with. What units does the capacity of a water heater tank have to be measured in? In the United States, where the imperial system is in use, the capacity of a water heater is measured in gallons of water. The most often seen capacities are between 40 and 60 gallons. Litres are used to measure the holding capacity of a water heater in nations that use the metric system instead of the imperial system.
Storage Tank Water Heater Sizes
the image’s source If you decide to go with a typical storage tank water heater, there are two things to keep in mind.
- In a busy 1-hour period, the amount of hot water consumed by your family is known as peak hour demand. The First Hour Rating (FHR) of a water heater is the amount of hot water that the water heater can produce in one hour.
Make some calculations in order to ensure that you choose a water heater that is the proper size for your residence. You should add up the total heat energy required by all of your home’s hot water equipment that you anticipate will be used in a period of one hour. Using the chart above, calculate the average number of gallons of hot water consumed by each of these devices using the formula. Consider the following scenario: two showers are taken, and the washing machine is started in the meantime.
- During that one-hour period, you would require a water heater with a “first hour rating” of at least 72 gallons in order to avoid running out of hot water.
- An ordinary family of four would consume around 200-400 gallons of water each day for activities such as dishwashing, bathing, laundry, and other household chores.
- The size of the tank is mostly determined by how much water you use each day, rather than by the number of people in your household (some individuals use more water than others).
- Those who live in a large house with a master bath that is located on the other end of the house from the water heater will require a larger tank than those who live in a home with the majority of the water outlets located near to the water heater.
Tankless Water Heaters Sizes
They are ideal for larger families who require hot water from multiple sources at the same time or who have a large Jacuzzi tub in their bathroom. Tankless water heaters are great for saving money on water consumption and are ideal for larger families who require hot water from multiple sources at the same time or who have a large Jacuzzi tub in their bathroom. Because of their small size, they are easier to conceal than larger tank versions, which can be a problem with particular models. Tankless water heaters are measured in gallons per minute.
- Add up all of the hot water that you will be utilizing at the same time. Consider the following scenario: you want to hop in the shower but you also need to run the dishwasher at the same time. The average water consumption rates for each are as follows: 1.5 – 3.0 gallons per minute for a shower and 1.0 – 3.0 gallons per minute for a dishwasher. On the high end, that’s 6 gallons per minute
- The average groundwater temperature varies depending on where in the United States you reside, and how far north or south you are. Overall, people who live in northern climates will require a more powerful tankless water heater than those who live in warmer climates because it takes more effort to heat up cooler groundwater. Once you have determined the number of gallons per minute you require and the appropriate groundwater temperature, you can determine which tankless water heater is the most appropriate size for your home. After selecting a brand, most tankless water heater manufacturers will include a water heater size calculator on their website, as well as model suggestions once you’ve made your decision.
Whether you choose a tank or a tankless system, keep in mind that you should plan for the long term and consider purchasing the next size up in case your family expands suddenly (or if single you decide to get married).
Finding the proper size and kind of water heater does not have to be a time-consuming and complicated procedure. Within minutes, you’ll have the appropriate size water heater for your house, thanks to some simple arithmetic and personal preference.
Choose What Size Water Heater You Need Like a Pro
When searching for a new water heater, one of the first considerations to make is the capacity of the water heater you want to purchase (i.e., the number of gallons the tank holds). According to conventional thinking, you should get the greatest heater feasible. However, it is more dependent on the number of people living in your home as well as the water heater’s capacity to recover from a power failure. Every household member should have 10-15 liters of hot water, according to industry standards.
Examine the capacity of the water heater, as well as the First Hour Rating (FHR) and your own particular Peak Hour Demand computation.
- A 30-gallon water heater will be required for a family of two people. A 30-40 gallon water heater will be required for a family of three people. A 40-50 gallon water heater will be required for a household of four people. A 50-60 gallon water heater will be required for a household of five people. A 60-80 gallon water heater is required for a family of six or more people.
These figures are simply estimates, and they might differ significantly depending on how much hot water you consume during your busiest hour. In the Peak Hour Demandcalculation, the quantity of hot water that your house is expected to need during a busy one-hour period is taken into consideration. One hour rating (FHR) refers to the amount of hot water that may be produced by the heater in one hour. It would be beneficial if you additionally considered the fuel source and its physical dimensions.
Determining Tank Size Based on Family Size
Depending on the model, tank-style water heaters may hold anywhere from 30 to 80 gallons of water. For the majority of households, 40-60 gallons is adequate. However, once again, it is dependent on your overall hot water use. You must perform the arithmetic in order to determine the appropriate size for your home. To get you started, here’s a ballpark figure to get you thinking:
- Households with one to two people will most likely only require a 30-gallon water heater
- However, larger households may require a larger water heater. Two- and three-person households require a water heater with a capacity of at least 40 gallons. For a four-person family, a 50-gallon water heater is more than adequate. If you’re using electricity, 50 gallons will enough, and 40 gallons will suffice if you’re using natural gas or propane. Water heaters with a capacity of 80 gallons or 50 gallons for families with more than five members may be beneficial.
Keep in mind that the list above is only a guideline, and as a result, you will not be able to draw any firm conclusions from it. The amount of hot water required varies from family to household. For example, a three-person household may discover that a 40-gallon water heater is insufficient to fulfill their demands, yet the same tank capacity may be sufficient for a five-person family. Some people take longer showers than others, and some families have an excessive number of equipment and fixtures that drain hot water from the water heater, which might cause problems.
The following are some starting points for calculating your normal consumption:
- The quantity of persons who are bathing and the hour at which they are showering are also important factors. It is possible that heavy appliances will be utilized at the same time as people are showering. The capacity of the primary appliances that were utilized to fill the tank
- The frequency with which the bathtub is utilized. Is it better to fill the tub partly or completely? Do you have any plans to renovate your bathroom or kitchen in the near future? If that’s the case, will you be upgrading to a larger bathtub? Are you intending on having additional children or getting married in the near future, given that a water heater may last up to 15 years
- Consider putting one water heater for every two bathrooms in large residences, or one water heater per floor in multi-story buildings.
Evaluating the Peak Hour Demand and First Hour Rating
Now that you’ve performed the lifestyle audit described above and determined the Peak Hour Demand (PHD) and the First Hour Rating (FHR), you may go to the next step (FHR). This information will assist you in selecting a water heater that will meet your hot water requirements. What is the demand during peak hours? The quantity of hot water consumed during rush hour is referred to as the peak hour demand. In your house, it defines the time of day during which you consume the most hot water. Your busiest hour may be at 8 p.m., just before everyone goes to bed, or at 6 a.m., just before everyone rushes out the door to get ready for school or work.
What is the rating for the first hour?
Take note that this is not the same thing as the maximum capacity for holding water in the tank.
The FHR information may be found on the water heater’s Energy Guide Label, which is easily accessible. Below is a checklist to assist you in estimating your peak hour use. Always keep in mind that the peak-hour demand should be a bit lower than the first-hour rating of your heater.
- The amount of water used for hair shampooing (per household member) is 4 gallons
- The amount of water used for dishwashing by hand is 4 gallons
- The amount of water used for face/hand washing (per household member) is 4 gallons
- The amount of water used for showering (per household member) is 10-15 gallons
- 10-30 gallons for an automatic dishwasher and 10-30 gallons for an automatic washer (older clothes washers can consume up to 45 gallons of water, but current energy-efficient clothes washers use as little as 5 gallons).
In the case of a household of five, the following is how you would calculate your peak hour demand. If you have three people showering every morning, two people washing their faces, and one person shaving and washing the dishes by hand, you will consume an average of 74 gallons of water every day. If your peak hour usage is 74 gallons, you should seek for a water heater with an FHR of 76-80 gallons, according to the chart below: Worksheet for estimating peak hour demand and first hour rating (example)
|USE||AVERAGE GALLONS OF HOT WATER PER USAGE||TIMES USED DURING 1 HOUR||GALLONS USED IN 1 HOUR|
|Shaving (.05 gallon per minute)||2||×||=|
|Hand dishwashing or food prep (2 gallons per minute)||4||×||=|
|Total Peak Hour Demand||=|
My own personal example is drawn from my family.
|1 Automatic dishwashing||6||x||1||=||6|
|1 Clothes washing||10||x||1||=||10|
|Peak Hour Demand||=||50|
*The information in the preceding spreadsheet is based on my family’s use. The amount of time your family spends during peak hours will most likely differ.
Sizing a Tankless Water Heater
Tankless water heaters aren’t as prevalent as tank-style systems, although they are becoming more popular. Their popularity is progressively gaining ground, mostly due to the fact that they take up less space and lower energy expenses by 25 percent. If, on the other hand, you choose a tankless water heater, a whole other set of considerations come into play. It is not need to worry about the tank’s capacity because these devices do not have any water storage. You should, however, pay particular attention to the flow rate and temperature rise during the experiment.
In most cases, flow rate is expressed in gallons per minute (GPM).
- Dishwasher: 1.5 gallons per minute
- Washer: 2 gallons per minute
- Shower: 2.5 gallons per minute
- Kitchen/bathroom faucet: 1.5 gallons per minute
- Running bathtub: 4 gallons per minute
It would be beneficial if you utilized the same calculations that were used in the assessment of peak hour demand in your calculations. Add together all of the flow rates from all of the faucets and appliances that were in use at the same time. If, for example, you’re running three showers and two dishwashers at the same time, you’ll need a tankless water heater with a minimum flow rate of 9 gallons per minute or higher. The following step is to calculate the needed temperature rise in the water.
Here are some incoming temperature forecasts based on your geographic location:
- -40 degrees Fahrenheit in the northern sections of the United States
- 50 degrees Fahrenheit in the southern portions of the United States
- 60 degrees Fahrenheit in the southwest and southern California, as well as the Gulf states
When in doubt about the incoming water temperature in your location, you can make an educated guess using the 50 degrees Fahrenheit estimate. Alternatively, if you want to be more precise, you may turn on the cold water in your kitchen faucet and let it flow for a few minutes before measuring. Remove the metal end of a thermometer from running water and measure the temperature of the water to obtain an accurate reading of the entering temperature. For the sake of argument, let us assume that the incoming cold water temperature is 40 degrees Fahrenheit and the domestic hot water temperature is 120 degrees Fahrenheit The temperature would have to climb by 80 degrees Fahrenheit to achieve this.
In order to guarantee that your new water heater can satisfy your hot water demands, it’s a good idea to round up the figures a little. Fortunately, most manufacturers’ websites include a flow chart to guide you through the process.
Other Factors That Affect Water Heater Size
- The temperature of the inlet water varies depending on the place and season. The summer does not need as much effort as the winter does. Because of this, you must guarantee that there is sufficient hot water flow on chilly winter days. The temperature rise caused by tankless gas water heaters is often greater than that caused by electric water heaters. Some tankless water heaters are controlled by thermostats
- Gas-fired tankless heaters may create a temperature rise of 70 degrees Fahrenheit at a flow rate of 5 GPM, and the same temperature at 1.5 to 2 GPM through an electric type
- Some tankless water heaters are controlled by thermostats. This type of unit offers versatility since the temperature of the output water fluctuates depending on the temperature and flow rate of the entering water
Final Thoughts on Water Heater Sizing
Consider the following scenario: you are still unclear about the amount of water heater you require for your household and you seek advice from a certified plumber. Another alternative is to investigate tankless water heaters that are available on demand. Check out our Buyer’s Guide: What Type of Tankless Water Heater Do I Need for more information. DISCLAIMER: The information provided on HomeInspectionInsider.com is not intended to be professional guidance. Before beginning any job, you should contact with a competent expert and verify that all necessary permits have been obtained.
As an affiliate, HomeInspectionInsider.com participates in a variety of affiliate programs with other websites.
Hot Water Heater Buying Guide
Taking a cold shower or paying high energy bills are not something anyone wants to do. Hot water heaters are important because they provide cost-effective and dependable hot water for your household.
Purchasing a Water Heater
Whether you’ve just experienced your first unexpectedly chilly shower or just want to lower your energy bills, investing in a new hot water tank is a wise decision. Follow these procedures to avoid having to guess about your appliance’s operation and fix problems:
- Determine the source of the fuel
- Select the type of heater you want
- Find out how much capacity you have
- Take a measurement of the space
Water Heater Fuel Sources
To begin, identify the sort of fuel source that is currently in use in your home. The following table summarizes the distinctions between electric, gas/propane, and hybrid fuel types.
Electric Hot Water Tanks:
- To heat water, one or two interchangeable heating components should be used. Compared to other sorts, it is less costly. There is a wide range of high-efficiency alternatives available
- Sizes range from 28 to more than 100 gallons.
- It is necessary to use a burner to heat the water
- It also requires flowing air around it. It is not possible to keep flammable items near by
- Water heaters that use gas are more costly than electric water heaters. Water heaters that use less energy than electric water heaters
- Sizes ranging from 30 to 100 gallons are available.
- Make use of the energy in the air to heat the water
- It is possible to utilize either outside air or air from the room where it is being kept. Water tanks are available as built-in units or as add-ons to existing tanks. Electric water heaters that are larger than conventional models
- An early investment that is more expensive
- It is more energy efficient, which results in cheaper utility expenses. Sizes available range from 50 to 80 gallons.
Types of Water Heaters
When selecting a water heater, take into account the size of your household as well as the availability of utilities in your location.
This is the most often seen form of water heater. They feature an insulated tank where water is heated and kept until it is required. They are available in three different fuel types: electric, liquid propane, and natural gas. Water heaters powered by natural gas or propane often consume less energy and are less expensive in operation than electric versions of the same size. When purchasing a water heater, it is important to consider its energy efficiency as well as its annual operating expenses.
- Tankless water heaters do not have a storage tank for hot water.
- Because a tankless water heater simply warms water as it is consumed, it is often more energy efficient than a standard storage tank water heater because it is not required to keep unneeded water hot.
- A tankless water heater can only deliver a limited amount of hot water at a given time.
- These units are a fantastic solution for anyone whose needs do not generally require hot water from more than two sources at the same time.
- Utility water heaters are often available in capacities ranging from 2.5 to 19 gallons.
- Water heaters for mobile homes are available.
- All heaters must be certified by the Department of Housing and Urban Development (HUD).
- Electric heaters are often less expensive than gas heaters.
- You’ll also want to think about where you’re going.
If there is access to the water from the outside, a basic gas water heater will suffice. When installation, make sure to double-check your dimensions because mobile home door openings might be significantly smaller than those of a typical home.
Water Heater Tank Capacity
In the United States, storage tank water heaters are categorised based on the amount of water they can store in gallons. Identifying the amount of hot water your home requires on a regular basis is critical to ensuring enough hot water supplies throughout the year. With the exception of tankless water heaters, you’ll need a larger tank to accommodate a larger family. Another factor to consider when purchasing a storage tank water heater is the recovery rate, which refers to the number of gallons of water it can heat in an hour while simultaneously replenishing the tank.
If you want to utilize a tank water heater, you may use these suggestions as a reference to determine the size of the tank you’ll require.
Minimum Gallon Capacity Recommendations
30 gallons for a family of 1 to 2 people 40 gallons for a family of 2 to 3 people 50 gallons for a family of 3 to 4 people 80 gallons for a family of 5 or more people
Gas Water Heater:
Thirty gallons per person or every family of one to two people 40-gallon household (for 2–3 people) Fifty gallons per family of three or four people. Eighty gallons for a family of five or more
Space for the Water Heater
If you don’t have enough room for a standard-sized water heater, there are other options. All of these solutions give the same degree of performance and may be used with either electric or gas systems (natural gas or propane).
Lowboys or Short Water Heaters
These water heaters are both shorter and broader than a standard water heater. They contain the same amount of water as their larger counterparts while yet being able to fit into tight spots such as crawlspaces and below cupboards. Lowboys are available in sizes ranging from 30 to 49 inches in height and can store up to 50 gallons of water.
Tall Water Heaters
High-capacity water heaters are available in sizes ranging from 50 to 76 inches in height and can accommodate up to 100 gallons of water. They’re perfect for basements or garages where there isn’t a concern about height. In addition, hybrid water heaters require additional room in order to perform correctly, so be sure to read the manufacturer’s instructions carefully before installing one of these units.
This feature is available for electric water heaters and prevents the higher element from burning out if the appliance detects that there is no water nearby.
ENERGY STAR ®and High-Efficiency Ratings
It is the most trusted and government-backed emblem of energy efficiency on the market today. This grade assists consumers in saving money while also conserving the environment via the use of energy-efficient items and procedures. Consider investing in a high-efficiency water heater to save money while also benefiting the environment. The energy factor (EF) rating of a water heater is used to determine its efficiency. The greater the efficiency factor (EF), the more efficient the model. However, while some of the most energy-efficient versions may be a little more expensive initially, they are meant to be more ecologically friendly and to save you money over time.
This information provides you with a sense of how the water heater model you’re considering is projected to perform, and it also includes an estimate of the model’s yearly operating cost, if applicable.
A new generation of water heaters adapts the temperature and other operational aspects to your personal demands and usage patterns in a simple and easy manner. Improved energy economy, enhanced durability, and smarter performance are just a few of the advantages of choosing a heater that is integrated with artificial intelligence of this type.
A Premium Electronic Gas Valve
Certain gas water heaters now include an electronic gas valve, which is more efficient. This results in more consistent and precise performance for better temperature control and faster hot water recovery than a standard mechanical gas valve since it has fewer moving parts than a mechanical gas valve. Using a light-emitting diode (LED) indicator, you can validate that the pilot is lighted and get diagnostic input on how well the system is performing. With a thermopile, this novel valve can operate entirely on its own power.
Because there is no requirement for an external power supply, installation is straightforward.
Wi-Fi Water Heater Capabilities
Electric water heaters that have a Wi-Fi module are currently available on the market. It allows you to regulate the temperature of your water from a distance. Set up a customized schedule so that hot water is only accessible in your water heater tank when it is needed, resulting in significant savings on your energy expenditure. It will also give you an alarm if your hot water supply is running low.
Water heater accessories are available to help you increase the safety and efficiency of your water heater by enhancing its functionality.
The water heater’s expansion tanks are connected to the water heater by a plumbing system. It is the purpose of these water heater tanks to store the additional volume of water that can be created when cold water is heated in the tank.
Water Heater Timers
Hot water heater timers are linked into the unit’s electrical supply and may be programmed to ensure that the water heater only uses power during specific hours of the day or night. By only using the water heater when it is absolutely necessary, you may reduce your energy consumption and save money.
Water Leak Detectors and Alarms
Water leak detectors can be found on the floor or in a pan beside the water heater, depending on the model. A liquid leak or overflow will cause the alarm to detect the liquid and sound an audio alarm, alerting the homeowner that there is a problem. Some of these alarms are also integrated with Wi-Fi, allowing you to get notifications on your smartphone.
Water Heater Insulation Blankets
They are designed to be installed above the unit and to improve the insulating properties of the water heater. Heating systems installed in garages or other unheated areas benefit from the use of insulating blankets.
Water Heater Pans
There are many pans that sit beneath the heater and catch water from leaks or overflows produced by excessive pressure in the tank. The side of the pan features a hole for a drain hose, which may be used to remove any excess water.
Water Heater Stands
Water heater stands elevate gas-powered units off the ground, reducing the risk of a fire in the case of a flammable liquid spill in the immediate vicinity of the unit.
If you’re replacing an old water heater and installing a stand along with your new one, your measurements, piping, and venting will be affected as a result. It will be necessary to hire a professional to install it if you do not have extensive plumbing expertise.