How to Select a Tankless Water Heater

You've decided to invest in a tankless water heater – a great way to reduce your heating costs and ensure that you never run out of hot water. But which model is right for you? Not all tankless water heaters are the same; you're going to need one that will give you the temperature rise you need, at the flow rate you require.

Sound confusing? Here's a brief explanation of these terms:

Tankless Water Heaters and Temperature Rise

The temperature of the water coming into your home will vary depending on your geographical location, water source and elevation. Generally, the colder the climate, the colder your incoming water will be, and the more powerful your tankless water heater will need to be in order to heat your water to the temperature you desire.

When you subtract the temperature of the cold water entering the unit from your desired output hot water temperature, you get the "temperature rise." So, for instance, if your ground water temperature is 10°C (50°F) and you want your hot water to be 49°C (120°F), you will need a tankless water heater that gives you a temperature rise of 39°C (70°F).

Want to save money while conserving energy and helping the environment? Read more about government rebates for tankless water heaters.

Flow Rate of a Tankless Water Heater

Flow rate is calculated as the number of gallons that flow out of a hot water fixture each minute (gallons per minute = GPM). How many showers, baths or other sources of hot water are you expecting to run at one time? Figure out the GPM for each of these fixtures, and then add up all of those flow rates. For example, if you expect to use a shower with a flow rate of 2 GPM at the same time that you run your dishwasher at 2 GPM, you will need a tankless water heater that will give you a flow rate of at least 4 GPM – while also providing the temperature rise you require.

Keep in mind that the flow rate of a tankless water heater will vary depending on the incoming temperature of the ground water. The warmer the incoming water, the greater the flow you will get. So a tankless water heater that is suitable for warmer climates may not give you the flow rate you want in a colder climate.

Did you know that you can rent your tankless water heater? Rodman's Heating and Air Conditioning gives you this flexible, convenient and affordable option. Either set up pre-authorized payments or we can bill you through your Enbridge gas bill (where available).

Need help calculating temperature rise and flow rate for your new tankless water heater? Call Rodman's Heating and Air Conditioning - we carry a variety of tankless water heater models from Rinnai, and we can help you choose the best unit for your needs.