2 Key Factors To Consider When Sizing A Tankless Water Heater

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A tankless water heater is an excellent alternative to a traditional water heater. Tankless water heaters only heat water when you need it and forego the storage tanks of traditional water heaters. The way this works is somewhat simple. Incoming cold water is piped through the tankless water heater unit. The water heater heats the water in pipes, with a gas burner or electric heating element. This hot water is then piped to wherever it’s needed.

Not only can tankless water heaters save you money on your energy bills, they also provide a constant supply of hot water. However, if you don’t get the right size tankless water heater for your needs, you may find yourself running low on hot water.

When sizing a tankless water heater, there are two key factors that you should consider:

  1. Flow rate, or the amount of hot water your household will be using at peak times. This number, measured in gallons per minute, reflects the amount of water needed to use all water-related appliances at one time. This ensures you have enough water flow available if needed.
  2. Temperature rise. To determine this important factor, take the temperature you desire for your hot water and subtract from it the temperature of the incoming cold water. The result is the temperature rise, which is the number of degrees your tankless water heater will need to heat your water. For example, if you want your hot water to be 120 degrees and the water coming into your house is 40 degrees, your temperature rise would be 80 degrees.

With this information, you can then determine which tankless water heater is right for you, by researching which ones are rated with the highest temperature rise necessary at your peak flow rate.


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