How To Determine Water Heater Size

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.

  1. 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
  1. 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.

Related reading:

  • 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?
See also:  How Often Should You Change Your Fridge Water Filter

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.

  1. 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.
  2. This means that a family of five would consume 50 gallons of water each morning from 8:00 a.m.
  3. However, it is probable that you will consume more than 50 gallons of water to wash the dishes from your meal.
  4. 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.
  5. 63 gallons of water have been consumed by your family after everyone has done bathing, cleaning dishes, and doing laundry.
  6. 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.
  7. 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.

How do I know what size water heater I have?

Home/FAQ/How do I determine the size of the water heater I currently have? When obtaining a price for a new water heater, it is critical to know not only how many gallons your water heater holds, but also the measurements of the water heater’s exterior. The capacity as well as the height of your water heater will have an influence on the price of your water heater.

Determine the Size of Your Water Heater

  1. In this section, you can find frequently asked questions (FAQs). For the purpose of receiving an estimate for a new water heater, it is necessary to know not only how many gallons your water heater holds, but also the measurements of the water heater’s exterior. How much your water heater will cost will be determined by its capacity as well as its height.

Now you can have a look at our pricing table to discover how much a water heater with the capacity and height that you require will cost you in total.

Do I need a tall or short water heater?

Height, gallon capacity, and the necessary height for plumbing connections are the most significant variables. Water Heaters with a Short Lifespan This type of water heater is shorter and broader than a traditional water heater, allowing it to carry the same amount of water as its bigger counterparts while yet fitting into tight locations such as crawl spaces and beneath cabinets. Short water heaters are available in lengths ranging from 30 to 49 inches and can store up to 50 gallons of water.

Water Heaters that are over six feet tall Tall water heaters may contain up to 100 gallons of water and have a height ranging from 50 to 76 inches.

In addition to accommodating the height of the tall water heater unit, the area must also allow the height required to connect a pipe on top of the unit to the home’s plumbing system.

Please contact me at 520-488-0816 if you are unable to identify the size of your water heater or if you have any queries about whether a certain water heater will fit in your area. admin2016-01-17T15:54:08-07:00 a link to the page’s load

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.

  1. 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.

  1. 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.
  2. 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.
  3. 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).
  4. 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. You can figure out what size tankless water heater you need in three simple steps if all you want to know is “what size tankless water heater do I need.”

  • 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.

Include any hot water that you will be using at the same time. Consider the following scenario: you wish to take a shower while also running the dishwasher. Showers use 1.5 to 3.0 gallons per minute on average, whereas dishwashers use 1.0 to 3.0 gallons per minute on average. Depending on where you reside in the United States, you will have a different average groundwater temperature. On the high end, that is 6 gallons per minute. 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’ve decided on a brand, the majority of tankless water heater manufacturers will include a water heater size calculator on their website, as well as model suggestions.

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.

  • 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). As a general rule, you should get the largest heater you can afford. Although the number of people in your family and the water heater’s capacity to recover are important considerations, they are not the only ones. Every household member should have 10-15 gallons of hot water available at all times. A 50-gallon water heater should be plenty for a household of four people, according to this guide. Analyze the capacity of the water heater, its First Hour Rating (FHR), and your own unique Peak Hour Demand computation. The following is an estimation of the size of water heater you will require:

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.
See also:  Where Is The Hot Water Heater In An Apartment

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.

As a result, it all comes down to how much water a family consumes on a daily basis. 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.

  1. What is the rating for the first hour?
  2. Take note that this is not the same thing as the maximum capacity for holding water in the tank.
  3. The FHR information may be found on the water heater’s Energy Guide Label, which is easily accessible.
  4. 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
Shower 10 × =
Shaving (.05 gallon per minute) 2 × =
Hand dishwashing or food prep (2 gallons per minute) 4 × =
Automatic dishwasher 14 × =
Clothes washer 10 × =
Total Peak Hour Demand =

My own personal example is drawn from my family.

3 showers 10 x 3 = 30
2 shave 2 x 2 = 4
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.

The entering water temperature should be subtracted from the unit’s specified output temperature, which is typically 100-120 degrees Fahrenheit, in order to do this. 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

-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 gulf states;

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.

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.

Tankless

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

Storage tank

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. The greater the reliance on hot water in your house, the greater the recovery climb that will be required. Pros:

  • 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.

  1. It only takes one person to take a longer shower for the tank to be completely empty.
  2. If you’re thinking about taking the tankless way, your purchasing experience will be a little different.
  3. You must, however, keep the following two considerations in mind: The pace of flow and the temperature rise.
  4. 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.
  5. Before making a purchase choice, conduct some investigation and testing to determine the temperature of your ground water.
  6. 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.
See also:  Who Do You Call For Water Heater Repair

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?

It makes all the difference when it comes to your comfort and your utility costs whatever size of water heater you get when purchasing a new water heater. If you choose a size that is too tiny, you will run out of hot water before the conclusion of your showers. If you go too big, you’ll end up paying more for hot water that you’ll never use. In order to guarantee that you get the proper water heater size, consider the following: Tank or tankless water heaters? That depends on the sort of water heater you’re looking to purchase.

Continue reading for step-by-step instructions on how to select the appropriate size for both tank and tankless water heaters.

Sizing a tank water heater

You simply need to consider two figures in order to decide the appropriate size tank water heater:

  1. When it comes to peak hour demand (the amount of hot water your home consumes during a busy hour), The tank’s FHR (the amount of hot water a heater can produce in a given period of time)

The FHR, often known as the “1st-hour rating,” of the tank will be stated on the yellow EnergyGuide label. In order to ensure that your tank’s FHR does not fall more than 1-3 gallons short of your peak hour demand, Care2 provided the photograph. It is possible to determine your peak hour demand using the chart and techniques outlined below: Step 1: Determine the time of day when your household consumes the most hot water. Determine how many of the activities listed in the chart above will be completed in that one hour period.

Step 2: Compile the total number of average gallons of hot water that will be consumed within that hour.

A typical peak hour of demand for a household of three is illustrated in the following example.

According to the table above, a tank water heater with an FHR of about 70 should be sought after by the family mentioned above.

Sizing a tankless water heater

The size of tankless water heaters differs from that of tank water heaters due to the fact that they operate differently. As opposed to preheating a vast volume of water that is readily available at all times, they heat incoming water just when it is required. Tankless water heaters are measured in two ways: first, by their capacity.

  1. Flow rate (the number of gallons of hot water per minute that you anticipate using at any given moment)
  2. Temperature increase (the number of degrees that the entering water must be heated before it can be utilized)

Calculate your flow rate and temperature rise by following the instructions in the chart and instructions below: Step 1: Choose the hot water appliances that you anticipate running at the same time on a regular basis. Step 2: Add the average flow (in gallons per minute) of all of the appliances together. This represents the flow rate in your home. The third step is to figure out the highest water temperature you’ll want to utilize and subtract it from the entering water temperature. The temperature of the entering water in Minnesota is around 40 degrees Fahrenheit.

Your flow rate would be 4-5 GPM at that point.

The temperature rise is calculated by subtracting the entering water temperature (120 – 40 = 80) from the temperature rise.

Please keep in mind that a temperature rise of 80 degrees at a flow rate of 5 GPM is considered to be the maximum for most home tankless water heaters. If you want to save money on a tankless water heater, you may have to reduce the number of hot water-using appliances you use at the same time.

Need help sizing and installing your water heater?

If you live in the Minneapolis-St. Paul region and have more questions concerning your water heater, please contact us. Get in touch with MSP Plumbing immediately for expert guidance and a straightforward installation procedure.

What Size Hot Water Tank Do I Need?

As reported by the United States Department of Energy, water heaters account for 14 percent to 25 percent of a household’s yearly energy use. When it comes time to install a new hot water heater, it’s critical to select one that is the proper size for your house and family’s requirements. In the event that you purchase a unit that is too large, you may incur greater water and energy costs as a result of the additional stand-by time required to keep the hot water. A smaller water heater on the other hand increases the likelihood of running out of hot water and forcing your unit to run continuously in order to keep up with your home’s water demand; in addition, there will be a lot more wear and tear on your water heater, which could result in a shorter unit’s life expectancy.

Estimating Peak Demand – First Hour Rating (FHR)

Traditional storage tank water heaters must be able to keep enough water in the tank to fulfill the peak demand of your household. There is a First Hour Rating (FHR) on every water heater, which you will use to establish whether or not a certain storage tank is the proper size for your needs or not. In gallons per hour, this refers to the amount of hot water that the heater can produce (starting with a full tank of hot water). According to standard practice, the total number of people in your house is multiplied by 12, which is the average amount of hot water consumed by one person during their peak consumption period (typically 12 gallons).

How to Calculate Family’s Desired FHR

When selecting a water heater, be sure that the first hour rating is within a few gallons of the figure you calculated in step one. Choose from one of the calculations shown below to find the appropriate size of tank for your family’s requirements (you might need to adjust that figure a bit if you have a large bathtub, multi-head shower or other special considerations).

Typical Breakdown

  • 30 gallon water heater for 1-2 people
  • 2-3 people for 40 gallon water heater
  • 3-4 people for 40-50 gallon water heater
  • 5 or more people for 50-80 gallon water heater

Equation for Average Household:

  • FHR is calculated by multiplying the total number of persons in your home by 12 gallons. For example, four persons multiplied by twelve equals a 48-gallon water heater.

More Precise Measurement:

  • Calculate the most water-intensive times of the day for your household (morning, lunch, and evening). It’s important to keep in mind the number of people that live in your home
  • Use the grid below to estimate your maximum hot water use during this one-hour period of the day. Using this method, your FHR will be calculated. (This does not represent an estimate of total daily consumption.)

** A water heater model with an FHR of 36-40 gallons would be required for this family. One of the most important considerations when deciding what size water heater to purchase is determining the appropriate size water heater for your family. You might be wondering if a tankless water heater is a good option for you – you can have all of your questions answered by downloading our tankless water heater guide. Wes Holloway is an American actor. Wes has been employed at TLC for 14 years now. He has a great deal of expertise in the home plumbing industry.

What Size Water Heater Do I Need For My House?

Residential water heaters are typically available in capacities ranging from 40 to 100 gallon tanks. Typically, most homeowners find that a 40 or 50 gallon hot water tank is the most appropriate size for their needs and budget. Therefore, they are the two most commonly used dimensions in construction. Every household, on the other hand, has varied water consumption requirements. This is dependent on the amount of people that live in the house, the frequency with which water is used, and whether or not the water is used during peak hours.

On a practical level, this may mean that you run out of hot water while in the middle of your shower. Make contact with your local plumbers to receive FREE quotations and advice on installing a water heater.

How To Determine The Size Of A Water Heater Tank

A general estimate of the size of the tank water heater that their household would require is sought by the majority of homeowners before purchasing a tank water heater. This is due to the fact that the size of a water heater has a direct influence on its cost. The cost of a water heater tank increases in direct proportion to its size. Although it may be tempting, you should avoid trying to save money on your water heater by purchasing a smaller one since you will be left with insufficient hot water.

Furthermore, because it will be overworked beyond its typical capability, a water heater that is too tiny will break down more frequently.

In order to determine the heater tank capacity that will really function for your home, you must take into account two factors: 1.

Demand During Peak Hours Let’s take a deeper look at each of these variables one by one.

Tank’s FHR (1st Hour Rating)

The FHR rating tells you how many gallons of water a heater can generate in an hour at a specific temperature. This number may be found on the Yellow Energy Guide Label on the back of the label. (See below for further information.) As time passes, the water will continue to cool down at a rate determined by how rapidly you are using it up. Once this occurs, it will take a specific length of time for the heater to recover to its full FHR capacity. This time varies depending on the equipment, and it should be taken into mind while selecting a hot water heater.

Your Peak Hour Demand

Generally speaking, the FHR rating represents the amount of water that may be produced by a heater in a single hour. Located on the Yellow Energy Guide Label, this number is easy to remember. As you can see in the next paragraph, As time passes, the water will continue to cool down at a rate dependent on how rapidly you are using it up. Once this happens, it will take a specific length of time for the heater to recover to its full FHR capacity. Depending on the equipment, this duration might vary, and it should be taken into account when selecting a hot water heater.

How To Estimate Your Peak Hour Demand

Listed below are two methods (one straightforward, the other more difficult) for estimating your household’s peak hour demand. 1. It is simple to calculate Step 1: Compile a list of all of the people who live in your house. If you have a family member who visits regularly or on a regular basis (but who is not a full-time employee), such as a stepchild, include them as well. Step 2: Divide the number of persons in your family by 12 to get the total number of people in your household. This is the FHR (Federal Human Resources).

2.

The following procedure is employed by experienced plumbers when they complete all of the job for you:) The first step is to figure out when time of day (morning, noon, or evening) your household’s members use the most hot water during a one-hour window.

Using the table below, establish which of the activities listed are performed by members of your home during this high consumption period.

Make careful to multiply each action by the number of times it was carried out during that peak hour to get the most accurate results. Total Peak Hour Demand may be calculated by adding up all of the activities in a day.

Activity Average Gallons of Hot Water Per Usage (x) Times Used During 1 Hour (=) Gallons Used in 1 Hour
Shower 10 x =
Shave (0.5 gallons / min) 2 x =
Hands/Face Washing (2 gallons / minute) 4 x =
Hair Shampoo (2 gallons / minute) 4 x =
Hand Dishwashing (2 gallons / minute) 4 x =
Food Prep (2 gallons / minute) 4 x =
Automatic Dishwasher 6 x =
Clothing Washing Machine 7 x =
Total Peak Hour Demand

Water Heater Size Based On Number Of People In A Household

Here is a simple reference table that you may use to find out the appropriate tank capacity for your home if you don’t want to deal with any complicated calculations.

Family Size Water Heater Capacity
1-2 23-36
2-3 36-46
3-4 46-56
5-6 56-80
6-7 80-100
7 or more 100 or more

It is clear from this chart that a family of five, which is extremely typical in the United States, requires a water heater with a capacity of 56-80 gallons. However, take in mind that this is a very rough estimate, and it may not be true for the amount of water consumed by your home. This is due to the fact that this computation does not account for any particularly high water consumption requirements that you may have.

High Hot Water Usage Demand

From this chart, it can be seen that a family of 5, which is extremely typical in the United States, requires a water heater with a capacity between 56 and 80 gallons. But remember that this is only a rough estimate, and it may not be true for the amount of water used by your family. As a result, this computation does not take into consideration any abnormally high water consumption requirements that you may have.

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