Selecting the Right Size Tankless Water Heater

by Eccotemp Canada

Choose The Perfect Tankless Water Heater For Your House

Selecting a gas tankless water heater for your house should be relatively simple, especially with all the online resources to help you make the right decision. That said, the variety of choices available may be overwhelming. One of the first things to consider is the size of the electric tankless water heater you’re looking for.

What is a tankless water heater?

Before we dive into how you can select the right-size tankless water heater, let’s quickly outline what a tankless water heater is. Compared to traditional water heaters, tankless water heaters don’t have a tank and only heat water when needed - it’s that simple.

How do tankless water heaters work?

When you turn on a hot water tap, water at room temperature goes through the heating unit - where a high-intensity gas or electrical element heats it. The water heater shuts off once the hot water tap is turned off. From an energy efficiency perspective, heating water on demand is much more efficient than a traditional water heater.

When considering the size of a tankless water heater, there are two factors to keep in mind.

1. Flow Rate (GPM): This refers to how much hot water you will need at any given time.

2. Temperature Rise (ΔT): This is the difference between the incoming cold water temperature and the desired temperature.

How do you determine the right-size electric water heater to buy?

1. The first step is determining the maximum number of devices you want to run and their total flow rate. After this, add up their flow rates (gallons per minute), and you’ll have the desired flow rate you’ll want for your water heater!

2. Next, determining the required temperature rise is also key to figuring out the size of your tankless water heater. To get this number, you can subtract the temperature of your feed water from the desired output water temperature. On average, in Canada, the temperature of your feed water ranges from 35 - 42 °F.

3. After you’ve determined the required temperature rise, you can begin shopping around for a gas tankless water heater that meets the above requirements!

4.  Here’s a list of Eccotemp’s range of gas tankless water heaters, varying sizes depending on your requirements. To determine the right one, check each specification, where you can view the flow rates at a given temperature rise.