What Size Tankless Water Heater Do I Need?



The size means a lot! This statement is true in many cases, especially when you want to buy and install something in your house. You ought to be 100% confident that it will suit the chosen area and will not cause any inconveniences. Thus, many housekeepers give close heed to the size of their water heaters.

They frequently ask – What size tankless water heater do I need? Water heater sizes mean a lot because their location in the house is always different. You may opt for buying a small tankless water heater, as well as a pretty large model. Some people really prefer to buy the whole house electric tankless water heater. Therefore, size surely plays a vital role.

It is not that easy to answer this question because a lot depends on a particular situation. The main factors are:

  • The area in your house;
  • The model;
  • Flow rate;
  • Temperature;
  • GMP;
  • Type;
  • Climate.

Each point is crucial and affects the final decision. For example, the water heater sizes of a tankless water heater electric and a gas equivalent are will be surely different, and the differences will be great. Accordingly, no one will be able to answer this question for sure straight away. Luckily, we know how to help you. Read this informative guide, and you will find out how to define the required size of your water heater.

The Need for Hot Water

Each family surely has different needs and so will consume different volumes of hot water. Some families may be very economic and practical. They use as much hot water as necessary to take a bath or shower or wash the dishes after supper.

In the meanwhile, other families spend more hot water and are less economic. They may like to take hot baths for long, wash their cars, and so on. Accordingly, you should take into account the need for hot water that will be enough for your family. Perfectly, you should have enough water for all members of the family to use it simultaneously.

Consider Flow Rate

All water appliances have various flow rates. They are measured by GMP, which is deciphered as gallons per minute. This question will give you some headache because every time you turn on the water, you may use a different volume of it. For instance, taking a shower normally takes 2-3 GMP. Washing machines will require fewer gallons.

To solve this puzzle, you should determine the time when your family members use hot water. Register all the needs to define the maximum for your tankless water heater electric or gas.


Give Heed to Temperature

One of the typical mistakes of people who deal with heaters for the first time is to forget about the temperature. You should define the temperature difference for sure! Let’s review one simple case. You take a shower, and it requires groundwater 50 degrees of Fahrenheit when it enters the heater. In the meanwhile, your shower requires 100 degrees of Fahrenheit. Accordingly, the required temperature rise is 50 degrees.

The Value of Realistic and Maximum GMP

If you are attentive, you have already noticed that tankless water heaters have two values of GMP – maximum and realistic. You ought to understand their meaning!

  • Maximum – This indicator shows the highest water flow rate, which is for perfect conditions.
  • Realistic – It stands for the actual conditions because it is impossible to reach the maximum GMP due to various reasons and factors in our households.

The needs differ because of the climate as well! If you live in Texas, the need for cold water will be about 75 and 80 degrees Fahrenheit because the climate is very warm. If you live in Minnesota, the need will range from 34 to 38 degrees Fahrenheit because the climate is much colder. In the meanwhile, the indications change when we discuss hot water.

Obligatorily give heed to the input and output water temperature. You ought to be confident that your heater will be able to reach the necessary temperature for your needs in cold and hot water. Some households may need 3.5 GMP, which is the realistic flow rate.

Consider Electric and Gas Heaters

You should be also aware of the distinct differences between electric and gas water heaters. Firstly, let’s define the differences between tank and tankless models. A tank heater will take into account the tank where the water is poured in and heated. A tankless option simply counts the amount of water is required for the flow rate.

If you use the gas unit, you enjoy one great advantage – time! Gas units use propane, which heats water much faster in comparison to electric units. If you choose an electric unit, it may be more compact, but the bills for electricity may unpleasantly surprise you. A lot depends on its size and power. You should also give heed to the cost of gas and electricity in your region to define the most beneficial option.

Summing Up

Now, we would like to make a short summary of our guide. If you want to install a water heater, you should know its size. It depends on various factors from the area where you want to install it in the house to the climate you live in.

All the measurements can be done by you. In case you are not able to do them accurately or are in doubt, hire a qualified contractor to complete the task. Besides, you should be sure that you will be able to install it. Here again, a lot depends on the model, type, and size of your water heater. We can give you some quick and smart tips. You should:

  • Check the warranty;
  • Choose a reliable store;
  • Read customers’ reviews;
  • Ask for referrals;
  • Surf the Internet;
  • Find useful guides.

Finally, you may turn to a competent service if you don’t want to install it yourself.

What Size Tankless Water Heater Do I Need? was last modified: by