operating cost of water heaters << page 1   heat-pump water heaters Heat-pump water heaters use electricity to move heat from one place to another instead of generating heat directly. To heat water for homes, heat-pump water heaters work like refrigerators in reverse. Heat-pump water heaters can be purchased as integral units w/ built-in water storage tanks or as add-ons that can be retrofitted to an existing water-heater tank. These systems have a high initial cost. They also require installation in locations that remain in the 40°F to 90°F range year-round & contain at least 1,000 cubic feet of air space around the water heaters. To operate most efficiently, they should be placed in areas having excess heat. They will not work well in a cold space.   solar water heaters Energy from the sun can also be used to heat water for your home. Depending on the climate & water use, a properly designed, installed & maintained solar water heater can meet from half to nearly all of a home's hot-water demand. Two features, a collector & a storage tank, characterize most solar water heaters. Beyond these common features, solar water-heating systems can vary significantly in design. The various system designs can be classified as passive or active & as direct (also called open loop) or indirect (also called closed loop). Passive systems operate w/out pumps & controls & can be more reliable, more durable, easier to maintain, longer lasting & less expensive to operate than active systems. Active solar water heaters incorporate pumps & controls to move heat-transfer fluids from the collectors to the storage tanks. Both active & passive solar water-heating systems often require conventional water heaters as backups, or the solar systems function as preheaters for the conventional units. When purchasing a solar water heating system, compare products from different manufacturers. The Solar Rating & Certification Corporation (SRCC) provides a benchmark for comparing the performance of some solar water heating systems. The SRCC publishes performance ratings of both solar water-heating systems & individual solar collectors. These published ratings are the results of independent, third party laboratory testing of these products. All systems & collectors that have been certified by the SRCC will bear the SRCC label. Keep in mind, though, that simply having an SRCC label does not imply that the product has a superior performance. Carefully compare SRCC label information on different brands & models to ensure that you are aware of projected performance. Just choosing a solar water heater w/ good ratings is not enough. Proper design, sizing, installation & maintenance are also critical to ensure efficient system performance. Although the purchase & installation prices of solar water heaters are usually higher than conventional types, operating costs are much lower.   Consumer Tips Choose a water heater w/ an appropriate first-hour rating (FHR) by estimating your family's peak hour demand for hot water. Determine the appropriate fuel type for your water heater. Consider a heat-pump water heater (HPWH) that is more efficient than a conventional electric water heater. Even though a HPWH may have a high initial cost, it can save up to 50% of your water-heating bill. When purchasing a gas-fired unit, look for one w/ sealed combustion or power venting to avoid back drafting of combustion gases into the home. Everything else being equal, select a water heater w/ the highest energy factor (EF). Note that the EF of one type of heater is not comparable to another type. For example, an electric heater w/ an EF of 0.9 may cost more to operate than a gas heater w/ an EF of 0.7. Select a water heater w/ at least one & a half inches of tank insulation & a heat tape. Try to minimize the piping runs to your bathroom & kitchen. Install aerators in faucets & low-flow shower heads that may reduce your hot water usage by half. Repair leaky faucets & showerheads. A leak of one drip per second can cost $1 per month. For electric water heaters, install a timer that can automatically turn the hot water off at night & on in the morning. Install a heat trap above the water heater. A heat trap is a simple piping arrangement that prevents hot water from rising up in the pipes, thereby minimizing standby losses. Drain a quart of water from your hot water tank every 3 months to remove sediment that prevents heat transfer & lowers the unit's efficiency. Take showers. Baths use the most hot water in an average household. You use 15 to 25 gallons of hot water for a bath & less than 10 gallons for a 5-minute shower.     Related Plumbing Article • hot water heater maintenance   << page 1