It’s hot.
It’s hot in a way that has seen most major Texas cities hit three-digit temperatures every day this week (some clocking their hottest days of the year), and in a way that has almost the entirety of the state observing a relentless, big-red-all-caps EXCESSIVE HEAT WARNING. It’s hot in a way that has Texans, in every effort to stay cool, grasping at straws. Or, in this case, umbrellas.
If you’re one of the nearly 150,000 people who shared a recent viral Facebook post that pictures an umbrella planted alongside an outdoor air-conditioning unit, you know what I’m talking about. Posted by the Corpus Christi Crónica, the post reads, “Will your air conditioner work better when it’s under shade? Yes, according to the Department of Energy,” and it reports that “some Texan residents have started doing this years ago to help their HVAC unit during the hot Texas summer temps. Some residents say it has made a very noticeable difference in their cooling and electric bill.”
The claim was met with a healthy mix of gratitude and ridicule in the post’s comments. But is there more to it than a lot of hot air?
“What I think it could be about is shade in general. Vegetation and trees around the home, that’s actually a good idea and will help the unit to run better. But it doesn’t change anything if the actual metal is hot,” said Roland Arrisola, vice president of Stan’s Heating & Air Conditioning and the Texas Air Conditioning Contractors Association’s newly elected president. “These things are really made to sit outside in the heat all day.”
Arrisola has been in the HVAC business for thirty years, and he’ll tell you point-blank (but with a friendly laugh) that no, shading your condenser unit with an umbrella will not make a difference in how effectively it cools. In fact, it could make it run worse. There’s a possibility running a unit covered for too long could result in an “internal overload,” which sounds terrifying but essentially means the unit shuts off to, as Arrisola poetically puts it, “cool down so that it doesn’t kill itself.”
“It’s a great idea, and I totally understand why some people would think covering it is a good thing,” Arrisola said, before launching into an extensive technical explanation as to why you should absolutely not do that, no:
“AC is about transferring heat. A lot of times people think it’s about producing cold air. It is, to a point, but it’s really about transferring heat from inside to out. The unit is taking that warmer air it captured from inside to the condensing unit outside, where it disperses the heat. It has a coil on the outside, which is actually using ambient air to cool that refrigerant down. So it’s dispersing the heat and in turn cooling the refrigerant down. And then it just cycles again, over and over.
“So if all of the sudden we put a cover over that unit, like with an umbrella, it’s not going to be able to disperse the heat as efficiently, which will make the unit run hotter. It can’t cool the compressor down, which can varnish the bindings and in turn kill that compressor. It actually turns into acid. . . .
“So, yeah, the best thing is not to cover the outdoor unit.”
Arrisola instead stressed the importance of ensuring your outdoor unit has easy access to free-flowing air on all sides. Most units Stan’s installs adhere to manufacturer specifications that require six feet between the top of the condenser and anything above it (e.g. house overhang, trees) and twelve inches between the unit and the side of the house or surrounding walls and fences.
The original viral umbrella post claims the tip came straight from the Department of Energy. An online quote saying “Shading the outside unit can increase its efficiency by up to 10%” seems to tie back to a now-defunct URL on the department’s website. The quote could possibly be a misinterpretation of a 1996 study by the Florida Solar Energy Center, which stated that “estimated savings of air conditioner condenser shading from landscaping have varied from 2 – 10%” but ultimately found AC efficiency increased only around 1 percent when comparing the temperature of air entering shaded and unshaded outdoor units. The DOE now offers energy-saving AC tips that include positioning the “condensing unit where no nearby objects will block airflow to it.”
If you’re looking for quick tips and tricks to help your AC run better, there’s still hope. Put the umbrella down, and pick up your hose. In a now-viral response to a Texas woman who was giving the umbrella myth a shot, one TikTok user and HVAC specialist offered up some fresh advice: spray down the condenser’s vents thoroughly with a high-pressure hose to remove any debris or dirt. The TikTok has been viewed nearly eight million times.
“If that connector coil is dirty because you’ve mowed recently, it’s also keeping the unit from cooling the refrigerant down like it’s supposed to,” Arrisola said of the tip. Along with cleaning the unit’s vents, he championed the power of a fresh filter and regularly scheduled maintenance.
If you’re concerned your AC isn’t functioning properly because it’s running constantly, he offered this by way of comfort: “It’s going to. With the heat the way it is right now, it’s going to run. It’s a good time to be an AC guy. Not a homeowner so much.” It is, doubtlessly, a confusing time to be an umbrella propped over an AC condenser in Texas.
