Tankless water heaters deliver hot water on demand and without the energy waste associated with traditional storage-tank water heaters. In a tankless heater, a gas-fueled or electric element heats water as the water passes through — but not until you turn on a faucet or hot-water appliance, eliminating the need to store hot water. To properly size a tankless water heater, you need to gather some detailed information about your home and your family’s water use.
To properly size a tankless water heater:
- List the different faucets and appliances where you need hot water, and add up all their flow rates in gallons per minute. Your showerhead, for example, might have a flow rate of 2.5 gallons per minute.
- Next, calculate the temperature rise you need. Subtract the temperature of the water before it’s heated from the temperature you want your hot water to be.
- Once you know the flow rate and temperature rise, you can choose the correct size water heater.
- If you have a high flow rate, you may need to install more than one water heater. They can be installed in parallel to boost their total flow rate, or they can be installed in different parts of your home to serve different faucets or appliances.
In addition to size and the number of tankless heaters you’ll need, also consider whether you want a gas or electric unit. Generally, gas-fired tankless water heaters can provide a larger flow than electric ones. However, it takes a bit more work to install a gas heater, because you have to make sure it can properly vent. If you’re looking at electric tankless water heaters, you’ll need to know the voltage required to run it and the number of amps it uses — and make sure that your circuit breaker will support it.
If you need help to size a tankless water heater or choose a model that will work for your home, contact the professionals at the Rheem Pro Partner. We serve homeowners in Colorado and Wyoming.
Shower image via Shutterstock
