How to Determine the Right Size Tankless Water Heater for Your Home

If you have been thinking about upgrading to a tankless water heater, there are many benefits. But, there are also a couple of things you need to consider to find the right size one for your home.

Tankless Water Heaters

Tankless water heaters are the latest trend and they can significantly improve your home’s energy efficiency.

Your tankless water heater needs to be the right size to meet the needed expectations. Too large of a tank will produce too much water, defeating the purpose of a tankless water heater, which is overall energy efficiency. But too small of a water heater will not produce enough water.

There are two calculations to look at to determine the right size such as flow rate and temperature rise.


Flow Rate

The amount of water a tankless water heater can generate is measured by the flow rate. This is measured in gpms – gallons per minute. The higher the flow rate, the larger the tank.

Based on the below numbers, if you are looking to run your washing machine, while also taking a shower, you will need a tankless water heater that has a flow rate of at least 4gpm. This will always be listed on the tankless water heater.

The typical flow rate of fixtures around your home:

Bathroom Sink – 1.0gpm

Showerhead – 2.5gpm

Bathtub Faucet – 4.0gpm

Kitchen Faucet – 1.5gpm

Dishwasher – 1.5gpm

Washing Machine – 2.0gpm

Temperature Rise

Next is figuring out the temperature rise, which is determined by taking the temperature of the water when it enters the water heater and subtracting it by the temperature it needs to be when exiting the hot water heater.

All you need to know is the average temperature of the groundwater in your area. Your local plumber should be able to help you answer this.

For example, if you are in let’s say New Jersey, the groundwater tends to be pretty chilly, around 52 degrees. This means the water is 52 degrees when entering the tankless water heater.

To take a shower, we want the temperature of the water to be warmed up to around 102 degrees. To run your dishwasher, you want the water to be warmed up to around 120 degrees.

This leads to the temperature rise of your tankless water heater to be 50 to 70 degrees. This number will also be located on the tankless water heater.

How to Install Tankless Water Heater

If you ever need help to pick out the right tankless water heater for your home, always call your local plumber. You will generally want to find one that has at least a temperature rise of 50 and a flow rate of 8.0gpm.

The team at Rainforest Plumbing and Air can not only find you the right water heater but also help you install it. For the best east valley plumbers, schedule an appointment with Rainforest Plumbing and Air to learn more about installing a tankless water heater into your home.