What Size Water Heater Do I Need? Answered!

Do you want to get your hands on the accurate size of water heater that would be convenient for you?

The accurate size depends on your need and how much warm water you and your family use. Hence, you need to be concerned about a few factors before going for any particular water heater.

In this article, we will talk about how to examine the accurate size of the heater and what things you should keep in mind before buying any model. Let’s get started.

Different Water Heater Sizes

If you want to get random knowledge regarding different sizes of water heaters, here we go.

If you have a small family comprising 2 people, a 30-gallon water heater or 40-gallon water heater size would be enough for you.
But if your family comprises 3 people, then better go for a 40 or 50-gallon water heater.
A family with 3 to 4 people should choose a 50 or 60-gallon water heater.
A big family comprising 5 or more than 5 people has a better option as they should go for a 60 or 80-gallon water heater.

Well, keep in mind that these figures are just rough ideas, so you should never follow them blindly. We will further talk in detail about these figures as well.

How to Check the Right Water Heater Size?

Do you get to check the accurate size of the water heater? Let’s have a look at the points below.

Calculate Peak Hour Demand

If you want to know which bath water heater size would be enough for your family, calculate at which time of the day your family usually needs it. For instance, if all the family members bathe in the morning, then morning will be the peak hour.

The hot water is mostly used while taking showers, so the shower timings will depict how much gallon of heater would be enough for you.

Calculate the Peak Hour Shower Demand

Now you have to figure out the peak hours in which you usually need hot water and determine the water activities you usually perform in those peak hours.

For instance, if you take a shower during those hours or simply wash your face? Considering all these activities, you can add the gallons according to the requirement and need. The water heater size is already mentioned above.

FHR Rating Water Heater

All the water heaters have FHR, which stands for First hour ratings. It depicts how many gallons of water this unit will provide to the family members in an hour.

Hence, if the per-hour rating complements your peak hour demand, then that one will be the right option for you.

Here are the different bathroom activities per person that depict how many gallons of water would be enough.

For a shower or bath, a 20-gallon water heater would be enough.
For hair washing, 6 gallons of water is appropriate.
If you only wash your hand, 2 gallons is the right choice.
For dishwashing by hand, you at least need 6-gallon water.
If you do shave during that peak hour, 3 gallons is enough.
For running the dishwasher, you at least need 14 gallons of water.
If you want to run the clothes washer, you at least need 30 gallons of water.

While keeping this chart in mind, you can get an accurate estimation of the size.

How to Measure the Capacity of Water Heater?

This is not the same everywhere as some people measure in gallons while a few measure in liters. If you go to the United States, the measurement of water heater is in Gallons, so they measure water in a gallon.

The capacity is normally 40 and 60 gallons. On the other hand, there are a few countries that do measurements in liters, especially those that use matrix.

How to Check the Size of a Tankless Water Heater?

The size also depends on what type of water heater you are using. A tankless water heater is the most effective option if you have a big family of at least 5 members.

You can go for this option if you have a big tub in your bathroom. If you are also planning the same type of water heater, Let’s figure out how to check the accurate size.

The tankless water heater is measured gallon per minute, so if you want to take a shower and wash the dishes at the same time, then you approximately need 1.5 – 3.0 gallons of water for a bath per minute and 1.0 – 3.0 gallons of water for dishwashing per minute.
Now it also depends where you reside as groundwater temperature also matters a lot. If you reside in a north area then the tankless model must be strong enough, but if you reside in a warm area, then the model doesn’t need to be strong.
Once you have determined all the above-mentioned queries, you can easily know which tankless model would go best for you and for your family. You can also ask for different recommendations from the manufacturers as they also have a heater size calculator.

The process of choosing the right size of water heater is not at all complicated. You just need to be curious and well-informed about a few factors after which you will be able to get your hands on the right one.

Let’s have a look at a chart below that depicts all the activities and how many gallons of water you would need per minute for your tankless model.

For the sink faucet, 1 GPM gallon of water would be enough,
If you want to fill the bathtub, 3 GPM is the appropriate size.
If you want to take shower, you at least need 2.5 GPM water per minute.
For the dishwasher, 3 GPM is the right option.
For the Clothes washer, 3 GMP per minute is applicable.

FAQs – Frequently Asked Questions

Still, confused about a few points regarding water heaters? Let’s talk about more queries below.

Is a 50-Gallon Water Heater Enough for A Family?

It depends on the water activities they perform with the hot water. Normally a 50-gallon water heater is enough for a family of 4 people but it also depends on other factors. Hence, keep in mind all the points mentioned in this guide before making a final decision.

How Do You Determine the Size of the Water Heater?

If you want to know the accurate size of the heater, first ensure which is the peak hour in which you and your family need hot water. After that, think about the activities you perform during that peak hour.

It will better tell you what should be the actual size of your water heater.

Is a 40 Gallon Water Heater Big Enough for A Family?

The 40-gallon water heater is enough for a family of 3 people but again, it is a rough idea because the actual figure depends on different factors already discussed in this guide.

Calculate the peak hours where you require hot water and later figure out the activities you perform. The chart given above will give you the perfect idea.

What is the Right Size Water Heater for A Family?

It also depends on the family members. For instance, if you are a family of 4 people then the roughly estimate would be a 50 or 60-gallon water heater. If you are a family of 3 people, a 40-gal water heater can be the best option.

However, do not follow these rough estimates blindly because the actual process is already mentioned above. Follow that process if you want the perfect size of the heater.

How Many Showers Can You Have in A 40-Gallon Water Heater?

For a shower or bath, you at least need 20 gallons of water heater per person. Hence, for 40 gallons, only 2 people can get facilitated.

Final Thoughts

Finally, you got an idea that what size water heater you need to perform all the required activities with warm water.

If you are planning to buy a water heater sooner or later, do not jump into the final choice. You need to look for different factors before making the final decision.

The size matters the most among all the factors because if you mistakenly buy the wrong choice, you won’t get facilitated with it.

I have tried to cover all the relevant points that you need to know in making the right choice. The factors you should keep in mind are also mentioned above.

I hope this guide will help you make the right decision whenever you plan to buy a water heater. Take notes and follow the steps.