Heating domestic water is the second largest energy waster in American homes. A family of four will consume over 21 million BTU’s of energy for a typical 80 gallon electric hot water heater per year. That equates to over $1286 per year (at $.20 / KWH) just for hot water!
Right now, we are seeing lots of commercials for tankless water heaters, with claims of considerable money savings. How does a tankless heater work and how does it save money?
Tankless heaters only heat the water you use, as you use it, in contrast to tank types which keep 40 to 100 gallons of water hot all the time. With tank type heaters, the water in the tank cools as the heat dissipates to the room air. Even well insulated tanks will cool, forcing the heat element to bring the water back to the set point. That continuous cooling and reheating wastes energy with no real return on the cost.
Tankless heaters use the concept of “On Demand” heating. Much like the concept of “On Demand” cable or satellite, you pay for what you use as you use it. A tankless hot water system heats the water as you use it and shuts off when the water stops flowing. Tankless units can use electric, natural gas or propane as an energy source. And true to the name, there is no tank of water to cool and be reheated. Most tankless water heaters claim to be over 90% efficient.
The cost of a tankless water heater could run from $300 to $1800 plus installation. While these costs might seem high on the surface, most tankless water heaters will repay the initial installation costs in a few years. Federal and state tax credits my also reduce the initial costs.
What should you consider prior to purchasing the system?
1. The fuel used to operate the system. If you already have a natural or propane gas tank unit, you may be able to use the lines for the new tankless heater. If your present tank heater uses electric, you will need to check the line and service to see if it will handle the new heater.
2. Size of the unit. Tankless heaters are priced in gallons per minute flow rates. The higher the flow rate, the higher the price and the need for more fuel to operate the unit. A family of four will use considerably more water than that of a family of one or two.
A shower will typically use 1.5 to 3.0 GPM (gallons per minute). If your home has two or more showers that are frequently used at the same time, the water heater will need to be appropriately sized.
2. The average inlet water temperature. Obviously, colder inlet water temperatures will require more energy to heat.
3. A qualified plumber. The plumber used to install a gas powered unit must be qualified for gas installations.
4. If you are installing an electric powered unit, you will need both a qualified plumber and licensed electrician for the full project.
Solar hot water heaters may also be an option, depending on your geographic location. Solar hot water heaters require that a portion of your roof or another part of your property face south. Solar hot water heaters will be discussed in a subsequent posting.
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