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If you have been educating yourself about water heaters, here is some information to help navigate when to use a tankless water heater.

First, we will address the two main types of tankless water heaters, as well as when and where to use each.

Point-of-use tankless water heater

A point-of-use tankless water heater is a compact appliance that heats water instantaneously. It is small enough to sit under a kitchen or bathroom sink and supplies hot water at the rate of .35 to .5 gallons per minute. It is not intended to heat the water for a whole-home but it can provide enough for a faucet or dishwasher. It can also be added to a room already using a traditional water heater or whole-home tankless water heater to provide an extra supply of hot water for showers or other needs, where maintaining a hot water supply has proven difficult.

Automatic water heater

Whole-home tankless water heater

A whole-home tankless water heater is used to instantaneously heat water for a home. It heats an average of two to five gallons of water per minute. With a water-saving shower head, a shower is restricted to two-and-a-half gallons per minute. Faucets can also have water-saving valves added to reduce their flow to one-and-a-half gallons per minute. The fuel source used in the tankless water heater also makes a difference, as natural gas fueled tankless water heaters can increase the amount of hot water provided per minute, in comparison to electricity fueled tankless water heaters.

Although a whole-home tankless water heater doesn’t technically run out of hot water, it can be over-extended if multiple uses are occurring simultaneously. For example, if the dishwasher is running and someone takes a shower, the whole-home tankless water heater may not have enough hot water to maintain a consistent hot water temperature. The solution to this situation would be to add a second whole-home tankless water heater to provide more gallons per minute or add a point-of-use tankless water heater to the area experiencing hot water shortages.


Benefits of tankless water heaters

Traditional water heaters heat and store their full capacity of hot water. Depending on the size of the tank, this can be 40-gallons to 120-gallons of heated and stored hot water.

Tankless water heaters on the other hand, heat water instantaneously, so only the water needed is heated. The energy savings is typically 8-34% using a whole-home tankless water heater, which can add up to a hundred dollars of savings or more per year, according to

Some important considerations in purchasing a tankless water heater include:

  1. Size: Dependent on the number of people in your household, choosing a larger size tankless water heater will ensure enough heating capacity.
  2. Energy Efficiency: Check the Energy Factor and fuel type to help you save the most money over the long run.
  3. Fuel type and availability: Most tankless water heaters are fueled by electricity or natural gas, but there are other options such as propane and solar. See what is available in your area.
  4. Costs: Knowing that paying more for energy efficiency will likely increase your upfront cost, weigh this out carefully because spending a little more on the front end may save you considerable money over the next twenty years.

An additional benefit of a tankless water heater is its size and safety. The days of having a large appliance bound to a wall in the garage, basement or another room of your home are gone. The tankless water heater is only a couple of feet tall and a couple of feet wide and usually mounts on the wall inside of the home. Tankless water heaters have also been found to be safer and leak less often than their traditional water heater counterparts.

The lifespan of a traditional water heater is ten to twelve years but tankless water heaters last twenty years or longer when maintained properly.

Hopefully this information helps answer some questions about when to use a tankless water heater and the differences between each.

For more information about finding options to save energy in your home, contact us at Three Rivers Heating.