AC Cool-Off

Q: "Should I shade the compressor of my central air-conditioning system?"

Richard Trethewey programs thermostat wars
Photo by David Carmack

The compressor of my central air-conditioning system is located on the west side of my home, where it is exposed to direct sun at the hottest part of the day. Should I try to shade it somehow?
— Sam, Bartlett, TN


Richard Trethewey replies: Shade is nice, because a compressor does have to work a little harder when it's in full sun. The Department of Energy says shading a compressor can shave 1 to 2 percent off cooling costs. But airflow is much more important; it's the air moving over the compressor's coils that causes them to give up their heat. If the shading ended up reducing airflow around the condenser, you'd actually be making things worse. That's why it's important to keep fences, shrubs, and anything else that might block airflow at least 24 inches away from the compressor.


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