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Heat Pump Water Heater
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Heat pump water heaters (HPWH) work using the same premise as any heat pump. Heat pumps transfer heat from one zone to another and most achieve efficiency factors (EF) of 2 to 3. Heat pumps gain their efficiency by using electricity to move heat versus using the electricity to create it.
Heat pumps move temperature from a warm location such as an outside space in a warm climate, near a furnace, or from the basement, to the water storage tank. The heat pump uses a heat exchanger located within the tank to transfer the warmth to the water. Because the HPWH extracts heat from the air it delivers about twice the heat as a conventional electric water heater.
The byproduct of this water heating is air cooling. In some applications the units can act as both a water heater and air conditioner. Depending on needs such as condition of current water heater, HPWHs are available as independent units, or as add-ons to existing systems. Initial purchase and maintenance can make these an expensive choice especially when inexpensive natural gas is an option. In appropriate applications, the HPWHs save energy in almost every situation.
The downside to greater efficiency is a more complicated installation. HPWHs should be installed by professionals who can assist with choosing a water heating system that matches your needs. The investment costs can be recouped quickly when hot water use and electricity costs are high. HPWHs are most efficient in warm climates or when installed in a heated location, such as a furnace room. Because the efficiency and capacity of the HPWH decrease as air temperatures drop, cold ambient temperature locations should be avoided.
Maintenance of HPWHs is higher than with other options, sometimes requiring routine heat exchanger coil cleaning as often as every 3 months. Heat pumps are slower than electric water heaters by about 25%. While this may not be an issue often, if the demand for hot water exceeds the supply the backup heaters come on, reducing efficiency of the entire unit.
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Before you buy... Adhesives
Adhesives that need ventilation or can’t be around fire and sparks are usually laden with volatile organic compounds, or VOC’s. The dangers to human health from VOC’s are sufficient to inspire the development of adhesives with less or none of the dangerous chemicals. New adhesives do the same job with fewer environmental and health risks.
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