Fact check: Experts say shading an outdoor AC unit does not lower indoor temperatures

Dezimey Kum, USA TODAY
·3 min read
28

The claim: Putting a shade over an AC condenser helps lower the temperature and reduce energy costs

As millions of American face extreme temperatures, many people are searching for ways to stay cool. Some Facebook users claim shading an outdoor AC unit – known as a condenser – improves its efficiency and lowers temperatures indoors.

"I got one of our canopies out and put it over ours today......Our house WAS 88° thats with central AC and 2 window units going. Its NOW 75° INSIDE just with a little shade added," reads a July 10 Facebook post.

The post garnered over 18,000 shares and 3,000 reactions in less than one week.

But shading an AC condenser would have a negligible effect, mechanical engineers told USA TODAY.

The hot air that comes out of an AC condenser cannot escape effectively if a shade is placed over the unit. A condenser may run less effectively due to airflow restrictions caused by the shade, experts say.

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USA TODAY reached out to the Facebook user who shared the claim for comment.

Covering AC unit not effective

Placing a shade over an AC condenser can limit airflow and does not improve energy efficiency, according to experts. It can actually have the opposite effect.

A central AC unit works by moving the heat from indoors to outdoors, Dave Borowski, the director of technical training at American Residential Services, explained.

"Shading the condenser simply won’t make a difference in performance if the cover or canopy over an outdoor unit allows some of the rejected heat to recycle back into the unit," Borowski said. "The performance goes down while your electric bill would increase."

Wes Davis, the technical services director for Air Conditioning Contractors of America, said that placing a shade over an AC condenser would be statistically insignificant.

He referenced a 1996 Florida Solar Energy Center study that found localized shading over a central AC unit decreased electricity consumption by 3%.

"Typically, air is drawn in from the sides and discharged out of the top. If the unit uses a pass-through strategy, in one side and out the other side, there is less risk of recirculation," Davis said.

Victoria Vinall, a spokesperson for the U.S. Energy Department, told USA TODAY in an email exchange that there are other strategies.

"Trees could potentially reduce AC loads if they can reduce the temperature around the AC units, but trees also have the advantage that shading can also reduce the overall AC load for a building too," Vinall said.

"Cleaning outdoor units or clearing anything that could restrict airflow would make a bigger difference."

Our rating: False

Based on our research, we rate FALSE the claim that putting a shade over an AC condenser helps lower temperatures and reduce energy costs. Placing an umbrella or canopy over an AC condenser does not improve its efficiency or lower energy costs, experts say. Shading a condenser can reduce its performance because airflow could be restricted.

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This article originally appeared on USA TODAY: Fact check: Experts say shading AC unit does not improve efficiency