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The Sensible Home

Simple Devices Can Boost Efficiency


Question: Other than using large solar collectors, there must be some way to use the fall's warm weather to heat water and lower our bills. Are there such devices?

Answer: There are many special devices that save energy and improve your comfort, whether you have air-conditioning or not. Heating water is an obvious use, since the water heater is a huge energy drain. The heat lost from the tank makes your house hotter or pushes up your cooling bills.

One device is a small add-on heat pump water heater. These electric units heat your hot water efficiently year-round. On warm days, they operate like a window air-conditioner in your utility room. They dehumidify too.

They draw heat from the surrounding air, thus cooling your house. Instead of exhausting this heat outdoors, as an air-conditioner does, they are plumbed to your water heater, and this heat is used to warm the water. In the winter, they draw waste heat from the air around your furnace area.

A geothermal heat pump is another option for very hot or cold climates. If you want the most efficient cooling, and winter heating, especially in areas with high oil prices, a unit with a "desuperheater" is effective. These units rely on the fairly constant ground temperature to operate efficiently.

The desuperheater coil is built into the complete year-round system. When running in the cooling mode, the heat extracted from your room air is transferred to the water in the water heater tank. There are also add-on geothermal water heater-only models.

Still another simple device has the heat exchanger coils built into a special insulated base. Your water heater rests on top of the base. The heat from the air-conditioner is transferred into the water tank through coils in the base.

If you have an older central air-conditioner that runs well, consider using a dehumidifying heat pipe unit. It precools the return air before it passes over the standard cooling evaporator coils.

By precooling the return air, it is dehumidified much more thoroughly. The net effect: the output air is slightly warmer than before, but much drier. This is ideal for most allergy sufferers.

By far the simplest improvement is to add some extra insulation around your water heater tank. Place the back of your hand on the tank near the top. If it feels warmer than the rest of the tank, adding insulation will help.


Write for (or instantly download Update Bulletin No. 720, a buyer's guide of heat pump water heaters, geothermal/desuperheater units, dehumidifying heat pipes and cooling/comfort and water heating efficiency tips. Please include $3 and a business-size, self-addressed, stamped envelope and mail to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, OH 45244.

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