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Active solar
Active solar
Active solar heating systems use the same basic principles as passive solar heating but incorporate mechanical means to get the most out of the sun's energy.

These systems use liquid or air to absorb solar radiation in a device called a collector. The stored heat can then be distributed through a building's existing heat system.

The cost of an active solar heating system is determined by the size of the house, the existing heating system and local climate. But a system using 4-6 collectors to provide heat for a 2,000 square foot house can cost between $15,000 and $20,000, according to Apricus Solar, a global solar thermal systems company.

In terms of efficiency, the right active solar heating system can provide 40% to 80% of a home's heating needs, according to the Department of Energy.

During the winter, however, active solar heating systems are not capable of entirely replacing a conventional heating system.

But active solar heating systems can also cut down on other utility costs by heating water during the summer.

NEXT: Wood burning stoves

Last updated August 22 2008: 11:56 AM ET
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