What's So Great About Moving Heat?

There are several articles in this issue about heat pumps-both air source and ground source. Heat pumps are attractive because they extract heat from otherwise unavailable sources and move it to useful places, like inside homes and water heaters. It's like getting something for nothing. The heat pump's cousin, the domestic refrigerator, is proof that the technology can operate for years without a breakdown or even maintenance. There are some excellent examples of heat pumps greatly reducing heating costs. Ground source heat pumps in particular offer advantages with respect to energy performance, maintenance, and noise. So why is there still so much skepticism about heat pumps?

These articles make it clear that heat pumps rarely achieve their design claims. The heat pumps that perform as intended are unfortunately more than equaled by units that achieve little savings, incur high maintenance costs, or anger occupants with noise and cold drafts.

The problem rests mostly with the installation. A heat pump is much more sensitive to mistakes in the air distribution system than a gas-fired system, because with a heat pump the air must move faster. Yet the blunders in duct sizing, placement, and installation suggest that manufacturers have failed to train contractors in even the most basic elements of installation. Simple principles, such as placing thermostats and return air registers properly, are routinely ignored, leading to a lifetime of poor heat pump performance. The same errors occur in manufactured buildings, where heat pumps are becoming far more common. Articles by John Proctor in previous issues described similar problems-and solutions-in central air conditioning systems (see "Bigger Is Not Better-Sizing Air Conditioners Properly," HE May/June '95, p. 19, and "Sizing Air Conditioners: If Bigger Is Not Better, What Is?" HE Sept/Oct '96, p. 13).

Who is responsible for this sorry situation? It is easy to blame the heat pump manufacturers. If they would invest more in designing the units for easy installation and then train the contractors properly, many of these scandals wouldn't happen. The Japanese heat pump manufacturers, for example, switched to ductless (minisplit) systems precisely because they do not require such highly skilled installation personnel. Some U.S. manufacturers are catching on and are offering a heat pump that can be installed in manufactured homes at the factory. But the truth is that the whole building industry mind-set is to blame. Its focus on lowest first cost, its lack of concern for operating and maintenance, and its insensitivity to noise and discomfort virtually ensure that heat pumps and complex systems will be installed incorrectly much of the time.

There's a golden lining for the energy professional in this scandal. Heat pump problems will continue to offer an opportunity for business. An energy professional will probably learn enough from reading the articles in this issue to cure some of the most common complaints while saving the customer energy. At least the energy professional will have satisfied customers.

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