Should You Cover Your Outdoor AC Unit in Winter?

Quick answer: Usually no. Outdoor AC units are built to sit out in rain and cold, and many Central Texas outdoor units are heat pumps that run all winter, so a cover can block airflow and trap moisture. To keep leaves out of an AC-only unit, most manufacturers suggest at most a breathable cover over the top, removed before the unit runs again.

Is your outdoor unit an air conditioner or a heat pump?

Find out first, because a heat pump heats your home all winter and must never be covered while it might run. The two look almost identical from the yard. Signs you have a heat pump:

• The label on the unit says “heat pump” or lists heating ratings like HSPF2.
• Your thermostat has an “aux heat” or “emergency heat” setting. Aux heat vs. emergency heat explains what those mean.
• The outdoor fan runs on cold days, and now and then the unit puffs steam during a defrost cycle (when it melts frost off its coil).

If any of those fit, skip the cover entirely.

What can go wrong if you cover your AC unit?

A full cover traps moisture inside the cabinet. Rain and humidity still get in, and the cover keeps them from drying out, which speeds up rust and corrosion on the coil, fasteners and electrical parts. Several manufacturers warn against plastic or fully enclosing covers for exactly this reason.

• Mice and other critters move into a dry, sheltered box, and wiring makes a fine chew toy.
• If someone switches the system on while it’s wrapped up, the unit can’t move air.
• On a mild February day in Austin, you may want the AC or heat pump running, and you won’t remember the cover until something sounds wrong.

Will a cover protect the unit during a hard freeze?

No. Outdoor units are designed for cold weather, and a cover does little against a freeze like February 2021. A heat pump can ice up in freezing rain, and its defrost cycle is built to melt that off.

If the unit stays encased in a thick block of ice for hours, switch to emergency heat and call for service. Don’t chip at ice or pour hot water on it, because the coil fins bend and puncture easily. Can a heat pump keep up with a Texas freeze? covers cold-weather performance.

How do you keep leaves and acorns out of an outdoor AC unit?

For an AC-only unit that sits idle over winter, a breathable cover made for the top alone is a reasonable choice, as long as the sides stay open and it comes off before spring. Clear leaves out of the top grille and base by hand after the oaks drop. If debris has worked its way down inside the cabinet, leave the panels on and let a technician clean it, since the fan and live electrical parts sit behind them. Gold Eagle can clean it out and check the unit over on a scheduled visit.

What actually protects an outdoor unit in a Central Texas winter?

• Keep about 2 feet clear around the unit, the spacing the Department of Energy suggests for airflow.
• Keep gutters and roof runoff from dumping onto the unit. Water pouring from the eaves can freeze on it in a cold snap.
• Check that the pad is still level. Central Texas clay soil shrinks and swells, and a tilted pad strains refrigerant lines over time.
• Book a fall checkup if you have a heat pump. Here’s what a tune-up includes.

What should you do next?

• Check the label or thermostat to see if your outdoor unit is a heat pump.
• If it is, take off any cover now and leave it off.
• Clear leaves from the top grille and base by hand after the oaks drop.
• If you have a heat pump, book a fall checkup with Gold Eagle at our online scheduler or call 512-489-4653.

Related guides: Can a Heat Pump Keep Up With a Texas Freeze?, Aux Heat vs. Emergency Heat: What Your Heat Pump Thermostat Is Telling You and What’s Included in an HVAC Tune-Up?.

About Gold Eagle Services: This guide comes from the team at Gold Eagle Services, a family-run Austin HVAC, indoor air quality and mold remediation company founded in 2017. We’re licensed (TACLA119235 and RCO1783), insured and bonded, and we serve homes across the greater Austin area.

Need help with this in your home? Learn about our air conditioning repair and installation, or call 512-489-4653 to schedule a visit.

Related Gold Eagle service: Home maintenance plan