How do Tankless Water Heaters Work?
Tankless water heaters, also known as On Demand water heaters and Instantaneous water heaters, use heating elements to warm the passage of water rather than storing a limited supply of warmed water like a traditional hot water heater.
Typically, when you turn on your hot water, you tap into a supply of pre-warmed water in a storage tank somewhere in your home. Traditional hot water heaters are built to keep a supply of hot water at your disposal at all times. This means that your water heater continuously uses energy to warm water whether or not you need it.
Tankless water heaters, however, heat the water only when you ask for it. With these smaller on demand devices, you start the warming process when you initiate the flow of water. Cool water passes through a heating element and warms to a desired temperature before continuing on to the hot water lines. Rather than constantly warming the water, you begin heating the water when you turn on a hot faucet or an appliance.
Most tankless water heaters can deliver hot water at a rate of two to five gallons (7.6 to 15.2 liters) of hot water a minute, more than adequate for any average home. Gas tankless water heaters have the capacity to reach much higher capacities by connecting more than one in series with another. Flow rates depend on the type of heating element involved as well as the size of the device. Larger tankless water heaters have the capacity to heat and deliver larger amounts of water than smaller ones. Be sure to choose a size that has a flow rate that can adequately supply multiple uses in your home simultaneously.
The two types of tankless water heaters, electric and gas, both have high flow rates, but gas heaters typically have a higher flow rate than the electric alternatives.
- Electric Tankless Water Heaters – use electric coils or an electrically powered heating element inside the heater to warm the cool water that passes through.
- Gas Tankless Water Heaters – use gas burners to heat the water, usually warming it faster than those with electric heating elements.
Tankless water heaters come in many sizes and can be installed for use with single appliances or water lines or for an entire home. They can also be installed side by side for use in homes or buildings with large hot water needs. For an entire home, you can save up to 40% more energy just by installing one large tankless water heater instead of the traditional tank hot water heater. When installed at each hot water outlet, however, tankless water heaters can be up to 50% more energy efficient.
Tankless water heaters are also ideal for bathrooms and sinks that are far from the conventional hot water heater tank. Ordinarily under these conditions, you would waste a lot of water waiting for a warm stream from a shower or sink. With a tankless water heater, however, the heating element is small enough to be installed closer to the desired water access and is available almost instantaneously.
These small tankless water heaters are also perfect for outdoor use or in areas where space is limited. Poolhouses, outdoor kitchens, remote hot tubs, or outbuildings are great places for tankless water heaters. Since they take up less space and conserve energy, they are the perfect alternative to separate tanks or water lines for these smaller buildings.