Your AC could be costing you double if you skipped this simple maintenance task – trust me, I'm a HVAC technician

When the temperatures outside begin to climb, many of us seek solace indoors with AC, but when did you last clean your outdoor air conditioner unit?

You may have dusted the vents and changed the filters, but neglecting to clean your outdoor condenser unit could be doubling your energy bills, and risking damage to your AC when you need it most. I'm a HVAC technician, and I see this issue a lot.

But there is a simple fix you can do yourself. Here’s how to refresh an outdoor condenser unit properly when cleaning an air conditioner, and why this simple AC maintenance task can cut costs so effectively.

How to clean an outdoor air conditioner unit

Hosing down your air conditioner’s outdoor condenser unit when cleaning your HVAC system takes a few minutes, but can have a drastic impact when trying to cut energy bills.

Better yet, this backyard cleaning task usually only takes three steps:

1. When I hose down a condenser unit, I always shut off the power first at the disconnect box or breaker.
2. Then, I remove any leaves or twigs around the base of the unit by hand.
3. For the rinse, I use a garden hose, available at Walmart with a pressure control nozzle, with moderate pressure and spray from top to bottom. The goal is to push the dirt through the fins, not into them. Spraying side-to-side or with high pressure can bend the aluminum fins, which restricts airflow even more than dirt.
4. If the fins look clogged or haven’t been cleaned in over a year, I recommend using a foaming coil cleaner, such as AC-Safe Foaming Coil Cleaner, from The Home Depot. I let it sit for 5 to 10 minutes, then rinse thoroughly. It’s important not to spray the electrical components or the fan motor directly.

It is a fantastic maintenance task to lower your energy bills. I’ve seen systems run 10 to 15 percent more efficiently after a basic cleaning with nothing more than a garden hose. It also reduces the likelihood of parts wearing out prematurely. Dirt buildup can cause the compressor to overheat or strain the fan motor, which in turn shortens its lifespan.

It also has the potential to solve strange AC unit smells.

You don’t need to disassemble the unit for this kind of routine cleaning, but I always tell homeowners to use caution. If they’re not comfortable doing it, a spring tune-up with a pro is a safer bet as part of your annual HVAC servicing.

How often to clean an outdoor air conditioner unit

I recommend cleaning an outdoor air conditioner unit for homeowners at least a few times each cooling season, especially during spring and summer when pollen, grass clippings, and dust accumulate quickly. Even a thin layer of debris on the coils can make the system work harder and result in premature signs that it’s time to replace your AC.

When the coils are clean, airflow improves, and heat transfers more efficiently. That can reduce energy use and help avoid overheating, especially when using an AC during a heatwave, when systems are already under strain.

While we’re on the topic of condenser upkeep, I also recommend sticking to a regular AC maintenance schedule. Ideally, your system should be serviced once a year, preferably in the spring, before peak usage begins.

That includes checking refrigerant levels, inspecting electrical components, cleaning the AC drain line, and testing system performance.

Even basic maintenance, such as replacing filters every one to three months and keeping vents clear, helps prevent serious problems later on.

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FAQs

Can I use Dawn soap to clean AC coils?

While you can use Dawn dish soap to clean an outdoor condenser, it is often not necessary and is less convenient than using plain water and less efficient than using a foaming coil cleanser for a particularly grubby condenser.

Meet the expert

Josh Mitchell

Air Conditioner Lab was founded by HVAC and tech enthusiast Josh in 2014, as a way for him to document his findings on home air conditioners and cooling methods.

Neglecting your AC is not the only home maintenance mistake to never make in summer. Several other slip-ups could be costing you extra, too.