How To Choose A Water Heater For You Home

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A water heater is a common household item that is present in almost every house. It is the necessity of cold areas and we use it for hot water in the winter season. Choosing a water heater is not very difficult. But if you don’t know anything about it, you might end up buying a useless heater. It will not be according to your requirement or your needs. How to choose a water heater is, therefore, a worthy topic if you are going to buy a new one.

Water heater works for many years and you don’t even care about it when it is working properly. After its useful life of 8-12 years, it would not work as desired. Then, we think of replacing our old water heater and we get into how to choose a water heater. Choosing a water heater involves many aspects, its fuel, cost, maintenance, ventilation, and size. You need to know about these aspects before buying a new heater. So, we are going to discuss all these aspects in detail. This article will help you to choose the best water heater according to your usage.

How to Choose a Water Heater

To dive into how to choose a water heater we need to look at all its important aspects. The common and most important aspects that we will see are,

  1. Tank or Tankless
  2. Size/Capacity
  3. Fuel type

Tank or Tankless

Some water heater comes with an inner tank that stores water and heats it. It takes a certain amount of time that is several hours to heat the water. It stores a specific amount of water and capable of delivering several gallons of water every hour. In Tank-type water heater, First Hour Rating (FHR) is mentioned which tells the amount of water it can deliver per hour starting with a full tank. This helps to buy a water heater according to your water demand. We need to match our Peak Hour Demand with FHR.

On the other side, the tankless water heaters give water on demand. They do not store water; the water is heated when someone opens a faucet. They have the capability to deliver certain gallons each minute which is termed as Gallons Per Minute (GPM).

For sure, the tank type heater will take more space than a tankless heater. Both have their own advantages. If you are short with space, then a tankless heater will be a good idea.


The size or capacity of a water heater depends on the number of simultaneous users at home. It depends on your family member’s ages and usage. The capacity of a tank-type water heater is 20-120 gallons. These sizes are available in the market. Commonly 40, 50 and 60-gallon water heaters are installed at home. For a general idea of the number of people and gallons, see the table below.

This table will give you a general idea of the capacity of a water heater according to the number of users. To calculate the actual requirement, you need to look at your Peak Hour Demand of the day and the FHR (First Hour Rating) of your heater.

Calculation of Peak Hour Demand

To calculate your peak hour demand, follow the given steps.

  • Identify the hour at which there is the most usage of hot water at your home.
  • Identify the tasks at that hour.
  • Multiply the gallons used for a task and the number of the times it is performed in one hour.
  • By multiplying you will get the gallons used in one hour for a specific task.
  • Add all the gallons used in all tasks.

The average gallons of water for tasks are given in the table below,

For Example: At peak hour demand there are two people taking shower at your home, one person is washing dishes and one person is shaving. The peak hour demand will be,

Peak Hour Demand = Gallons used in shower x 2 + Gallons used in Dish Washing x 1 + Gallons used in

Shaving x 1

Peak Hour Demand = 10 x 2 + 7 x 1 + 2 x 1

Peak Hour Demand = 29 Gallons

Hence for this Peak Hour Demand, a water heater of FHR 30 Gallons or a little more would be suitable.

For Tankless water heaters, Gallons Per Minute (GPM) needs to be checked. It tells the hot water it can supply per minute.

Fuel Type

According to availability and affordability, you can select a specific fuel type heater. The most common fuel types are.

Natural Gas

Gas water heaters are the most economical water heaters. They usually come with a tank, but tankless are also available. If gas is not an issue for you, then it is a good choice. Further, these water heaters need ventilation.


Electric heaters are also very common, but its running cost is more than a gas water heater. They also have tanks in them. The best thing is that they do not require ventilation.


Propane is also used as a fuel. If there is the availability of propane in your area, then you can use this type of heater. They are usually available as instant water heaters without tanks. They require very little space.

Solar Energy

The running cost of a solar water heater is negligible or nothing. It is very expensive. They can operate in the day time and store hot water for the night.

Questions and Answers

What is the usual warranty period of water heaters?

The common warranty period is 10-12 years. Water heater typically works great for this period of time.

Do electric heaters need a ventilation system?

No, electric water heaters do not need any ventilation system. You can place it in non-ventilated areas as well.

Which water heater is most economical for residential use?

For residential use gas water heaters are very economical, they are very common. In the US 53% of water heaters are gas water heaters. They require ventilation and care.


To buy a new water heater, you should know how to choose a water heater. We have covered all the aspects which are necessary for choosing a water heater. This guide on how to choose a water heater will be very helpful for you.