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A Quick Guide To Optimal Air Conditioner Clearance

Optimal Air Conditioner ClearanceIf you’ve had an HVAC technician come to your home to give your air conditioner and furnace a maintenance check, you’ll know that they look at the system inside and outside the home. If you haven’t had a pro out to perform maintenance yet, there is no time better than the present, especially if you want to keep your AC running smoothly for the rest of the summer. One of the easy items you can check in the meantime is the clearance around your air conditioning unit. After all, your AC relies on the magic of airflow, so you need optimal air conditioner clearance to keep it working well.

Room To Breathe

It’s a tough job being an air conditioner. Think about everything it takes to keep you cool – from grabbing heat from indoor air (or air circulating inside) and then rejecting the heat outside of your home. It’s a constant cycle that relies on good airflow to get the job done!

Now tack on all the outside elements that can hamper airflow around your outside unit – trees, shrubs, bushes, fences, decks, landscaping, etc. that can block that transfer of heat. Your AC will need to work extra hard to create cool air if it needs to battle all those things, and will waste money and energy in the process unless you clean up around your unit.

Knowing how much room your AC needs depends on the style of your unit, says Keith Hill, technical support manager for Minnesota Air. So, you need to first look at your manufacturer’s manual to find out the amount of clearance your unit needs around it in order to run at peak performance.

“I live by a rule of 1-foot on all sides as the absolute minimum for shrubbery and the back of the unit facing the house,” says Keith. “In an alcove or any situation where two walls are adjacent to the unit, then I’d keep an 18” clearance as a minimum.”

The more space the better when you have walls, fences, or compost bins near the AC. Air can’t flow as easily around those solid objects.

Keith says most modern units are top discharge units, where the air blows straight up. If you have a top discharge AC, then you want to make sure there isn’t anything obstructing the airflow above your unit.

“For example – building a deck over the top of the unit. That’s always a bad idea. It takes a lot of free area to allow the rejected hot air to find its way out of the area,” he says. “Any impedance to this upward flow creates a recirculation loop – hot air being drawn back into the unit. This causes the unit to operate at much higher temperatures. If you are recirculating the discharge air on a 90-degree day, the unit may be drawing in air at 110 degrees or more, depending on how much is recirculating.”

Keith says it’s generally good for the top of the unit to have 8-feet or more of clearance to make sure the rejected air doesn’t get recirculated back into the home.

“It’s been my experience that most units installed under a deck fail long before their expected life span due to compressor failure,” he says. Plus, the operating costs will be much higher, so you can see why it’s important to maintain those clearances.”     

To help ensure you have enough clearance around your AC, here is a handy cleaning checklist with some reminders:

  • Clear obstructions within 12-18 inches around your outdoor unit.
  • Remove anything above your unit that’s within 8 feet from the top of the unit (branches, tall overgrown bushes, overhanging plants/ baskets/ bird feeders).
  • Are obstructions a safety hazard? Not usually, but they do impact efficiency, the lifespan of your unit, and cooling capacity.

For more tips on maintaining your air conditioning unit, click here, and always make sure to talk to an HVAC professional, like the experts at, to find out more ways to make your home efficient.

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