Benefits of Tankless Water Heaters

A tankless water heater is shown on a wall in a basement.

Choosing the tankless water heater that’s right for your household is important to ensure that you’ve got enough hot water on demand. Some of the top considerations when looking for a new tankless water heater are the energy efficiency and technology used. That’s where tankless, often called “on-demand,” water heaters come in.

A huge technological achievement, these innovative systems show significant energy savings over tank-type water heaters, saving you money, reducing your carbon footprint and giving you valuable living space back as well.

In this guide, we’ll give you some tips on how to choose the best tankless water heater for your home.

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Tankless Water Heater Types

Whole House Unit

A whole house tankless unit would be installed in a central location and completely replaces a standard tank water heater.

Point-of-use Unit

A point-of-use unit provides hot water for a single fixture. Typically, this would be a sink located far from a central hot water source. Because of its very small size, a point-of-use unit is usually located right under the sink.

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What Are the Benefits of a Tankless Water Heater?

Enjoy huge savings on your energy bills - in some cases you could save up to 50%!
Endless supply of instant hot water.
No storage tank saves valuable space.
Lifespan up to twice as long as conventional tank water heaters.

How Do Tankless Water Heaters Work?

Tankless water heaters provide an endless supply of hot water for as long as it’s needed. Because these systems provide hot water on demand, they don’t require a storage tank to store hot water. No storage or holding tank means that tankless water heaters have a life span twice as long as traditional systems because the risk of rust and corrosion is significantly lower.

Gas-powered Tankless Water Heaters

Gas-powered systems are fuelled by propane or natural gas and heat the water with a burner.
A tankless gas water heater needs a gas line to the water heater, and the unit must be vented to the outside.
If tankless gas is replacing a gas tank-type water heater, typically it requires a larger gas line. Venting may also need to be upgraded.
The right size unit can provide endless hot water for up to two major applications at a time. This unit is a great replacement for a tank water heater.

An electric tankless water heater is shown.

Electric Tankless Water Heaters

Tankless electric water heaters heat the water with an electrical element and are a great replacement for a tank model.
A tankless electric water heater needs to be hardwired to the circuit breaker/electrical panel. The size of the existing electrical service to the home needs to be considered as larger units may require an upgrade.
Although tankless electric water heaters may output fewer GPM than a tankless gas unit, the larger electric units can provide endless hot water for up to two major applications, which is sufficient capacity for most homes.
They are less expensive to purchase than gas tankless, and their smaller size and lack of venting may allow them to be installed where gas tankless units cannot go.

A tankless water heater next to a washer and dryer

What Size Tankless Water Heater Do I Need?

When choosing a tankless water heater, you need to make sure that you’ve got the right size to accommodate your household. To choose the right size, there are a few things to consider.

How Many Products in your House Need Hot Water?

How many water-using products you have throughout your home. This includes any bathtubs, showers, sinks, washing machines, etc.

The Combined Flow Rate (GPM) of These Products

Most items like shower heads and faucets will list their flow rate in GPM (gallons per minute). You’ll need to add the flow rates of all of the items you think may possibly run at the same time and select a tankless water heater size with at least that amount of GPM to be sure that you’ve always got hot water on demand.

Temperature Rise

You’ll also need a water heater that accommodates your climate by using an adequate temperature rise. For Canadians, our temperatures can dip quite a bit, so you’ll need to make sure that you select a tankless water heater that can heat your water to the desired temperature easily. Remember, warm incoming water allows a unit to output a higher GPM than cold incoming water.

A bathroom faucet with running water flowing

What is GPM?

GPM or Gallons Per Minute represents the amount of hot water a tankless water heater provides per minute.

Fixture/Appliance	Average GPM or Flow Rate
Bathroom Faucet Flow Rate	0.5 – 1.5 GPM
Low Flow Kitchen Faucet	1.0 – 2.5 GPM
Shower Head Flow Rate	1.0 – 2.0 GPM
Dishwasher Flow Rate	1.0 – 2.5 GPM
Washing Machine Flow Rate	1.5 – 3.0 GPM

To calculate the best tankless water heater size for you, add the GPM for all the appliances and fixtures you plan to use at the same time. If you wanted to run a dishwasher and shower at the same time you would need a water heater with a minimum 2.0 GPM , for example.

Should I Replace My Existing Tankless Water Heater?

There are a few signs that it’s time for a water heater replacement or repair.

Your water isn’t heating enough or at all.
You notice water leaking around the heater.
You’re experiencing low water pressure.

If you’ve got any of these issues, you may need to repair or replace your tankless water heater.

An installer installs a tankless water heater in a basement.

Want to Have a Tankless Water Heater Installed?

Contact a Home Services installer to learn more about having a tankless water heater installed in your home. Consider these questions before your free in-home consultation:

Do you want to power your new water heater by the same source as the old heater (e.g. gas or electric)?
If you are considering a gas unit, does your home already have a gas line and if so, what size is it?
Ideally, where would you like to install your tankless water heater?

Learn More

Related Resources

Gas-powered Tankless Water Heaters

Gas-powered systems are fuelled by propane or natural gas and heat the water with a burner. A tankless gas water heater needs a gas line to the water heater, and the unit must be vented to the outside. If tankless gas is replacing a gas tank-type water heater, typically it requires a larger gas line. Venting may also need to be upgraded. The right size unit can provide endless hot water for up to two major applications at a time. This unit is a great replacement for a tank water heater.

Electric Tankless Water Heaters

Tankless electric water heaters heat the water with an electrical element and are also a great replacement for a tank model. A tankless electric water heater needs to be hardwired to the circuit breaker/electrical panel. The size of the existing electrical service to the home needs to be considered as larger units may require an upgrade. Tankless electric water heaters do not need to be vented. Although tankless electric water heaters may output fewer GPM than a tankless gas unit, the larger electric units can provide endless hot water for up to two major applications, which is sufficient capacity for most homes. They are less expensive to purchase than gas tankless, and their smaller size and lack of venting may allow them to be installed where gas tankless units cannot go.