How Big of a Water Heater Do I Need (Best Sizes Revealed)

Have you ever been the last one in the shower only to find that there’s no hot water left? Painful, right? If you don’t want to get stuck taking cold showers, this guide on water heaters is for you. In this guide, we’ll answer your most pressing questions, including the one on everyone’s mind: how big of a water heater do I need? 

For a family of 4, a 50 to 60 gallon water heater is recommended. With a family of 5 or more, you will need at least a 60 to 80 gallon heater. Of course this could change depending on the age of the people in the house, as well as how long and hot of showers/baths they take.

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We’ll also be sharing a few tips on how to pick the best-size heater for your home and we’ll walk you through how you can calculate your daily water usage, especially during peak hours. These numbers help narrow down your options as far as picking the best size and type of water heater.

How Big of a Water Heater Do I Need

The size of your ideal water heater depends on who will be using it and how much hot water is needed. The size and layout of your home also play an integral role when it comes to heater selection. The bigger the home, the higher the demand will be for hot water.

Some people opt for a small tank to save space and money. The problem is you may end up not having enough hot water for all your household needs. Not to mention, it may actually cost you more money by having a smaller unit, especially if you tend to run out of hot water.

That’s because it costs more money to reheat an entire tank of water than it does to maintain the heat. If you have a tank that’s bigger than what you need, chances are you will not deplete it entirely, thereby saving in the power needed to reheat it.

Then, there are those who are on the opposite side of the spectrum; they think that by buying a larger water heater means that there will be more water to heat, which in turn means more power will be needed.

This is true if you totally deplete the tank of hot water everyday!

However, the cost of maintaining the hot water in a 40 gallon tank will not cost much more than if you were to have a 60 gallon tank.

Here’s a basic guide for water heater sizes based on the number of people living in your household:

  • 1 – 2 people: 30 to 40-gallon tank
  • 2 – 3 people: 40 to 50-gallon tank
  • 3 – 4 people: 50 to 60-gallon tank if it’s electric or a 40-gallon tank if it’s powered by liquid propane or natural gas
  • 5 or more: 60 to 80-gallon tank if electric or a 50-gallon tank if it’s powered by liquid propane or natural gas

What Are the Different Types of Water Heaters

There are three types of water heaters on the market. Each type has its own benefits and drawbacks. The difference between them is mainly in the way they’re powered.

Let’s discuss each type in detail. 

Tank Water Heaters

Storage tank water heaters are the most commonly used heaters. They consist of an insulated tank that heats and stores the water.

Tank water heaters can be powered by electricity, natural gas, or liquid propane. The fuel source determines the size of the heater, as well as its yearly operational costs. It also determines how energy efficient the unit will be.

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Tankless Water Heaters

One of the main advantages of tankless water heaters is they generate hot water when you need it. When you turn on the hot water faucet, the cold water moves through the pipes. This is where it’s heated via an electric element of a gas burner before flowing out of the faucet as hot water.

Despite their advantages, tankless water heaters have one major drawback: they limit water flow rate. On average, these heaters provide anywhere from 2 to 5 gallons of hot water per minute.

This isn’t enough if several people are using hot water at the same time. To meet the demand, you can install a couple of more tankless heaters around your home.

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Solar Water Heaters

Solar heaters are energy-efficient and low-maintenance. Although, their initial installation cost can be quite high.

Another drawback is that if your hot water usage increases on cloudy days, you’ll need a backup system. This can be either a traditional tank heater or a tankless system.

The tanks on solar-powered heaters have different capacities than standard tank water heaters. They come in three main sizes:

  • Small: 50 to 60-gallon tank, ideal for 1 – 3 people
  • Medium: 80-gallon tank, ideal for 3 – 4 people
  • Large: over 80 gallons, ideal for 4 – 6 people

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How Can I Determine My Daily Water Consumption

To make sure you’re getting the right-sized water heater for your home, you’ll have to do a bit of basic math. First, make a list of all the devices that use hot water in your home.

Now, let’s assume you’ll be using all these devices at the same time within an hour. This is what’s known as ‘peak hour demand.’

Here’s a sample list:

  • Shower/bath: 20 gallons
  • Hands/face washing: 4 gallons
  • Shave: 2 gallons
  • Dishwashing by hand: 4 gallons
  • Automatic dishwasher: 14 gallons
  • Automatic clothes washing machine: 32 gallons
  • Preparing food: 5 gallons

Let’s say during one hour, you run the washing machine, dishwasher, and shower at the same time. This means that you need a water heater with a first-hour rating (FHR) of 66 gallons per peak hour.

The FHR refers to the number of gallons of hot water the water heater can provide in a single hour. This is taking into account that the heater has a full tank of hot water. In the above example, the best option would be to get a 70 or 75-gallon tank heater.

Typically, the FHR can be found on the EnergyGuide sticker located on top of the water heater itself. You can also find it on the manufacturer’s site under the heater’s “performance” or “specifications” section.

Another factor you have to consider is the recovery rate of your water heater. This is the amount of water it can heat in an hour. The more your family depends on hot water, the higher the recovery rate needs to be.


Finding the right-sized water heater for your needs isn’t as difficult as it may seem. All you need to do is add up a few numbers to figure out how much hot water you need during a typical peak hour.

The next step is to pick the heater of your choice. Make sure it’s within a couple of gallons of your FHR. Also, don’t forget to factor in the recovery rate so you’re not left stuck without any hot water.

Once you’ve calculated these two numbers, you can breathe a sigh of relief. You’ve done all the hard work. Now, all you have to do is wait for the heater to be installed. Then, you can fill your tub with hot water and enjoy a nice, relaxing bath!

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