April 2018 EnergyWiseSM Tip: Heat Pump Water Heaters
When has being in "hot water" ever been a good thing? If you have a heat pump water heater, it is a great thing!
According to the 2015 Customer Appliance Saturation Survey of Nebraska’s residential customers, more than half of Nebraska homes use electricity to heat domestic hot water. When it comes to energy use in homes, after space conditioning, water heating is the second biggest consumer of energy and accounts for about 13 to 18 percent of total energy used in homes. By using heat pump technology, energy for water heating can be cut by 50 to 80 percent. That is because heat pump water heaters use electricity to move heat into their storage tank instead of generating heat directly.
Heat pump water heaters come in a variety of configurations. Most often, they are a stand-alone unit that resides in a home’s utility room. However, other designs employ their own outdoor compressor/evaporator coil, integrate with an air-source or geothermal heat pump system or have their own geothermal system.
How do they work? The common stand-alone type operates like a refrigerator in reverse. While a refrigerator pulls heat from inside itself and dumps it into the surrounding room, a stand-alone air-source heat pump water heater pulls heat from the surrounding air and moves it into a storage tank to heat water.
Stand-alone heat pump water heaters require installation in locations that remain between 40 to 90 degrees Fahrenheit and provide at least 1,000 cubic feet of air space around the unit. Cool exhaust air can be exhausted to the room or outdoors. Installation in spaces with excess heat, such as furnace rooms, works best. Heat pump water heaters will not operate efficiently in a cold space, as they tend to cool areas they are in.
Heat pump water heater systems typically have higher initial costs than conventional storage water heaters. A stand-alone, 50-gallon heat pump water heater sells for more than $1,000, with other configurations costing even more. By comparison, conventional electric hot water heaters start closer to $400. However, according to the Energy Star® website, a heat pump water heater can save a household of four people around $330 a year on their electric bill. That adds up to a net savings of more than $3,300 over the 13-year life of a typical heat pump water heater.
Keep in mind that a stand-alone heat pump water heater is going to remove heat and lower the temperature of the room where it is installed. While it may seem counter-intuitive to locate it in a space you already pay to heat, there are many other sources of heat in the home to include solar gain through windows as well as heat from cooking equipment and other appliances. Often, a room with a clothes dryer or a utility room with a furnace is an ideal location. During the cooling season, heat pump water heaters help remove excess heat and humidity that an air-conditioning system would remove anyway. The cumulative effect is energy savings while heating and cooling your home, as well as creating hot water.
Another consideration is that heat pump water heaters have a slow recovery rate. This is why larger units and/or backup electric heating elements often make sense for homes with higher hot water consumption.
Finally, check with your local electric utility to see if you are eligible for an EnergyWise SM heat pump water heater incentive starting at $200 per qualifying unit or a low-interest loan by upgrading. They also have additional ideas on other energy-saving improvements that make getting into hot water a great thing!