How often should you cover your air conditioner?
Grumpty's answer
Every 6 months
Why bother
Protects the unit through the off-season. Standard upkeep. Dull and cheap, and a lot less dull than whatever it's quietly preventing.
What the job involves
- Skip the full waterproof cover. The pros, Lennox among them, all say the same thing: a sealed cover traps moisture against the unit and turns it into a snug rodent nest, which rusts the wiring and can void the warranty. The condenser was built to sit out in the weather. Let it.
- If you want to keep falling leaves and seeds out of the fan, fit a breathable mesh cover that shields the top only, hanging no more than about 6 inches down the sides so air and damp can still move. A weighted scrap of plywood laid on top does the same job for nothing.
- Before the off-season, clear the leaves and muck from around the unit, leave it at least 2 feet of clearance on all sides, and hose the fins down if they've gone grimy.
- Through winter, knock the heavy snow off and clear any icicles forming above it so nothing drops into the fan. Pull any cover off before you run the AC again, or the unit can't shed its heat.
Do it yourself, or pay someone?
DIY for everyone. A breathable mesh top cover is about $20 to $40, or lay a weighted bit of plywood on top for nothing. No reason to hire it out. If you'd sooner have a pro do a fall clean-and-inspect than cover it at all, a condenser coil cleaning runs about $75 to $230.
Signs it's overdue
- Leaves, seeds, grass clippings or cottonwood fluff packed into the top grille or matted against the side fins.
- A full vinyl or plastic cover left on tight all winter, with damp, rust spots or signs of nesting underneath: droppings, chewed insulation. That's the cover doing harm, not good.
- Icicles hanging off the eaves directly above the unit, lined up to drop into the fan.
When to start thinking about it
A few days' warning does it. Grumpty grumbles 5 days out, then leaves you alone. Mark it done and Grumpty sets the next one, every 6 months, so you can go back to forgetting it exists.
Questions people ask
Should I cover my air conditioner in winter?
Not with a full waterproof cover. The makers, Lennox included, advise against it. A modern condenser is built to run outdoors all year, and a sealed cover traps moisture, which rusts and corrodes, and draws in rodents that chew the wiring. Cover it wrong and you can void the warranty. The most that's worth doing is a breathable, top-only cover to keep debris out of the fan.
What's the harm in just throwing a tarp over it?
A tarp is the worst of the lot. It seals off the airflow, so condensation builds underneath and rusts the coils and wiring, and it makes the warm, sheltered nook rodents love. None of the HVAC pros surveyed recommend it. And if you forget it's there and the AC kicks on, the unit can't shed its heat, which risks real damage or a refrigerant leak.
If I don't cover it at all, will it get damaged?
No. The unit's built for it. The only real consequence of leaving it bare is leaves and debris collecting inside over the season, which means more spring cleanup and, if you let grime build for years, a condenser coil cleaning at about $75 to $230. That's far cheaper and far less bother than the rust and pest damage a full cover invites.
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Stop keeping this one in your head
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