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Regular maintenance is the most important thing I can do to ensure an air conditioning system lasts as long as possible.
The good news is that anybody can save money by cleaning their own air conditioner.
I put together this guide that goes over everything I do during the cleaning process so you can do it yourself.
ACLAB Note:
Air conditioners should generally be cleaned once or twice yearly to remove dirt, ensure adequate airflow, and maintain energy efficiency.
Considerations before I get started
There are always three things I consider when I’m playing out an air conditioner cleaning:
- 1Before getting started, I advise researching your system to get familiar with it. Determine where the indoor and outdoor units are located, then consider any challenges in accessing them.
- 2Be careful navigating the attic, and try to go up there early in the morning to avoid the heat. Attics can easily exceed 140 degrees Fahrenheit during the peak of summer where I live, so it’s best to work before or after the sun is out.
- 3Sometimes, air conditioners are not easily accessible. For instance, an outside unit may be elevated off the ground, or the indoor unit may be in a very tight space. In these cases, it may be best to call a professional.
ACLAB Note:
Whenever in doubt or if you feel you do not possess sufficient skills, it is always best to leave the cleaning task to the professionals.
What I use
Cleaning a central air conditioner unit doesn't require a lot of specialty tools or cleaners.
Most air conditioners are easy to disassemble with basic tools that you already have, like a screwdriver.
As long as the unit is cleaned regularly, a garden hose with a good nozzle is the only cleaner I need.
However, if maintenance was neglected for years, a more powerful cleaning solution may be necessary.
Here are the tools and supplies I use to clean dirty air conditioners:
How I clean my own AC unit (step-by-step guide)
I like to clean and inspect my AC units at least once per year.
Since my own air conditioning unit is located in the attic, I always start with the indoor unit when I clean it. From there, I move outside to take care of the outdoor unit.
Here are the exact steps I follow when I clean my own air conditioner.
Keep in mind that many of these steps work on a ductless mini split, package unit, or window unit.
Turn off the air conditioner and prepare the indoor unit
The first and most important thing to do before working on or cleaning an air conditioning unit is to turn the system off.
I start by flipping my thermostat to the "Off" position, then isolate and tag the circuit breaker. This ensures the fan doesn't kick on while I clean the evaporator.
With the system off, I head over to the indoor unit. Unfortunately, mine is in the attic, but older homes often have them in a closet.
After squeezing into the attic and turning the lights on, I take the side access panel off. There are a handful of screws that hold the side cover on.
I carefully remove each screw and set the cover to the side.
Inspect evaporator coil and add pan tablets
Now that the cover is off, I inspect the coils as much as possible and check the drain pan.
I look for any dirt in the unit’s main pan and notice if any water is pooling in it.
Once I finish looking over the coil, I add pan tablets to the condensate drain pan. These will help prevent algae from growing and clogging the drain lines.
If the evaporator coils are dirty, they must be cleaned. I use a spray bottle from the air return side to lightly rinse the dust off the coils without making a mess.
A coil cleaner or a mix of soapy water also helps clean the coils.
The biggest problem is usually accessing the dirty coils. I have steps in my air return to make cleaning the coils easy.
However, most AC companies don’t install air conditioners with ease of service in mind.
Therefore, it may be necessary to separate the air handler from the return plenum or install an access panel in the plenum.
ACLAB Note:
It’s worth noting that most HVAC companies do not clean the evaporator coils as part of their annual maintenance.
Additionally, dirt and debris on the coils indicate that a better air filter is needed.
Clean the drain
I always take a moment to look at the overflow pan. If there are signs of water or rust, then the air conditioner is leaking because of a clogged drain line.
This is commonly caused by debris buildup in the drain lines and should be addressed immediately by a professional.
My drain has a removable cap, so I can use compressed air to clear it out. If a drain is really clogged, I would use a drain snake, but typically an approved drain cleaner in the pipe once every three months keeps everything clean.
This is the best way to keep the drain lines clear of algae buildup from trickling condensation.
ACLAB Note:
Some people pour bleach down their AC drain to keep it clean, but this is not a practice that I recommend. Bleach will not dissolve mineral build-up, and can lead to corrosion of the AC drain line and evaporator coil.
Related article: How to clean AC drain line
Reassemble indoor unit
With the system all cleaned out, it is time to put the covers back on. I ensure each panel goes back on in the proper orientation and that each screw is in.
I’ve encountered a few air handlers that were taped to ensure a good seal.
My air conditioning unit is not taped, but I always replace any cut foil tape when reassembling an air conditioner.
The last thing I do before closing up the attic is check my media air filter. I have an Aprilaire media filter that does a great job of trapping dirt.
Best of all, it only needs to be changed once a year, so I make it a point to check and replace the air filter when performing my semi-annual cleaning.
Related article: Top rated HVAC leak sealants
Pull the disconnect for the condensing unit and remove the top
Next, I move outside to the condenser to begin cleaning it. I start by pulling the power disconnect, which should be mounted to the side of the house near the air conditioner.
Power is no longer going to the unit with the disconnect removed, so it is safe to begin cleaning.
I start by taking off the screws that hold the top of the condensing unit.
I also remove the screws for the service cover and remove it. Depending on how large the unit is, it’s often a good idea to get a helper to lift the top off.
Before taking the top off, I always check the fan motor wires. Some units have long fan wires that will allow the top to sit next to the unit.
However, my air conditioner has a replacement fan motor, and the wires are now very short.
The solution is to unplug the fan motor and slip the wires out of the unit. Be sure to discharge the capacitor before trying to disconnect the wires.
ACLAB Tip:
I like to take a picture of the wiring configuration on every unit to make reassembly a bit quicker.
When I pull an air conditioner’s top off, I always set it on the ground upside down.
I never set it down on the fan blades because the thin metal will bend and get out of balance.
I like to take things one step further by removing the sides of the condenser. The side panels on mine easily slide out to completely reveal the coils.
Some systems do not use stamped metal sides (most notably Carrier), so the fins are easily accessible.
Hose out the condensing coils
With the top off, I grab my hose and spray out the dust and debris stuck in the coils. I do not turn the faucet on all the way, and I set the nozzle to a wide stream.
The pressure mustn’t be too high with a narrow stream to avoid bending the fragile aluminum fins.
Some people choose to forego a nozzle altogether and just flush a ton of water through the fins. However, I find that doing so makes a gigantic mess and floods my yard.
I’ve seen some people on the internet using a pressure washer to clean out coils, which should never be used since it can easily bend the fins.
The actual cleaning process is very straightforward. I work the stream up and down, spraying straight at the fins from the inside of the air conditioner. I work around the unit until it is clean.
While the unit is apart, I also take a minute to look for and remove dirt and debris, such as leaves at the bottom.
My unit has a composite base, so I don’t have to worry about rusting, but many older air conditioners had metal bases that could literally fall apart.
Visually inspect capacitors
Before closing the condensing unit back up, it’s a good idea to take a moment to visually inspect the capacitors.
It’s impossible to determine if they are bad just by looking, but bulging is a sure sign that the capacitor is on its way out.
Similarly, capacitors can actually pop and leak, requiring even more repairs.
ACLAB Tip:
If I notice that a capacitor is starting to bulge, I will replace it immediately. It is a cheap part that can lead to major headaches if it fails in the peak of summer.
Reassemble the condensing unit and insert the disconnect
Now that the outdoor unit is clean, I reassemble it by putting the sides back on. Then, I put the top back and rerun the wiring for the fan motor.
If necessary, I will zip-tie the wires so they don’t get caught in the fan blades before I reconnect the fan motor as it was.
Next, I put all of the screws back into the sides, top, and access panel. Finally, I finish up by inserting the disconnect.
Check refrigerant levels (if certified)
Before buying a set of manifold gauges, remember that anyone who works on HVAC lines must be EPA-608 certified.
This ensures that the person knows how to properly connect to and service a unit without losing any refrigerant.
Every couple of years, I add this extra step, which is checking the refrigerant levels.
However, many HVAC companies check levels as part of an annual cleaning.
Checking the levels helps determine that the system may have TXV problems or other components that may need repairs before they worsen.
Replace the air filter and check the temperature
The final step I do when cleaning my AC involves replacing the indoor air filter and turning the system back on.
I use cheap air filters inside in addition to my media filter, so this is a good time to check and replace that one.
ACLAB Tip:
Check the manufacturer’s instructions when replacing filters and install one with the proper micron rating.
However, people with undersized ductwork may not be able to use these thicker air filters.
After replacing the filter, I also dust off the return grille cover with a cloth rag to remove any dust buildup. At this time, I also like to wipe off each supply vent with a rag or duster.
After replacing the air conditioner filters and cleaning the grilles, I head to the thermostat and turn the air conditioner back on.
To finish up, I like to use a thermometer to measure the delta between my return and supply ducts. This isn’t a necessary step, but it gives me a good idea of how well the system works.
Related article: AC not turning on - Causes and fixes
How often do I clean my air conditioner
I clean my air conditioner twice per year in the spring and fall.
The spring cleaning prepares the unit for the 100+ degree summers and ensures it runs efficiently.
Then, I like to clean it again in the fall to spot any potential problems from running those long hours.
I use this opportunity to remove dead leaves from the outdoor unit and prepare them for winter.
Factors that affect how often to clean your AC
Whenever someone asks a question about their air conditioner, I always start by explaining how usage impacts maintenance and longevity.
I have a heat pump, so the compressor runs through the summer and winter. That is a major reason why I clean it twice a year.
However, I’ve worked on air conditioners whose owners kept their thermostats very high, so the system ran infrequently.
Therefore, cleaning it once per year was more than enough.
ACLAB Tip:
Taking a closer look at the indoor unit, I advise people with gas furnaces to have a professional check their unit in the spring to ensure it is safe.
I also consider whether the homeowner has pets and what type of filter they use.
Homeowners using the basic mesh filters will need their units cleaned more frequently, as do people with cats or dogs.
Seasonal upkeep and maintenance tips
- 1The most important thing a homeowner can do to maintain their air conditioner is to change the filter. I have seen countless air conditioners that were either missing a filter or the filter was plugged with dirt.
- 2A common problem that arises from a dirty system is frozen evaporator coils. An insufficient amount of air moves over the unit’s coils, which leads to them turning into a block of ice. Be sure to write the replacement date on the filter or use the filter function on smart thermostats.
- 3Air filters were typically designed to last 30 days, but pleated filters with high MERV ratings may last up to 90 days. However, I inspect my filter every 30 days and replace it sooner if it starts looking dirty.
- 4Another thing I like to remind homeowners is that they should use caution when cutting their grass. It is always best to discharge grass away from the condensing unit. Additionally, I recommend turning off the air conditioner while cutting the grass around the outdoor unit to avoid dirt and debris getting sucked into the coils.
What to avoid when cleaning central ACs
Before putting on a tool belt and heading up to the attic, there are a few factors to consider. The first is whether the system has a warranty.
Some HVAC companies require the systems to be professionally cleaned regularly to maintain warranty coverage.
I highly recommend calling the installer and asking about the warranty coverage before cleaning the system yourself.
Warranty information can typically be found in the manufacturer’s instructions under regular maintenance or necessary maintenance.
ACLAB Note:
It is important that you read the warranty terms. In some cases, cleaning the unit yourself or with unsuitable cleaning agents may void your warranty.
I also warn against cleaning systems that are difficult to access. Outdoor units in low-lying regions are often elevated, which makes cleaning them a dangerous chore.
Similarly, I would never advise cleaning an indoor unit for someone who isn’t comfortable navigating an attic.
Finally, it is vital to remember that air conditioners use high-voltage electricity, and connectors may not be insulated inside of these units. Hosing water on these components can be a recipe for disaster.
Always shut off the thermostat and disconnect power before working on an air conditioner.
Flipping the circuit breaker for the indoor and outdoor units is one way to guarantee that power is completely turned off before cleaning.
Other ways to clean your AC
Cleaning with mild dish soap
The first time someone asked about cleaning their coils with dish soap, I honestly was a bit confused.
I always used a cleaner specifically designed for AC coils, which delivered great results.
Over the years I've heard from homeowners whose previous AC techs didn't properly flush out the coil cleaner which left their home smelling bad for days or weeks.
Since then, I have started keeping non-foaming dish soap on me.
A major benefit is that it is very cheap, smells good, doesn't damage the coils, and customers seem happier.
Sometimes, I dunk a brush into a small bucket of soapy water, but I also picked up an attachment that fits on a garden hose and mixes the soap.
Just remember to rinse out the soap when you're finished cleaning.
Coil cleaner
While I use coil cleaner less than I used to, it is still one of the most powerful tools in my arsenal.
Homeowners can buy foaming coil cleaners at most big-box stores. The stuff sold in these stores should be safe to use on both indoor and outdoor coils.
However, spraying any remaining coil cleaner with clean water is critical.
Leaving coil cleaner on the evaporator or condenser can actually cause damage over a prolonged period of time.
The main reason that I pull out coil cleaners is when the coils are literally caked in dirt. This is pretty rare, but it does happen depending on how often the unit was serviced.
But more recently, I even started going behind coil cleaner with soap to ensure the acidic cleaner is completely removed.
Cleaning with a hose and water
The majority of cleaning can be done with just a garden hose. A nozzle creates a steady stream that is just strong enough to spray out the dirt wedged between the fins.
Best of all, water will not damage the coils as long as the stream isn’t too powerful.
Install a larger air filter rack
My last recommendation for cleaning an air conditioner actually doesn’t involve cleaning at all.
If the evaporator coil frequently gets dirty, it may be a good idea to install a larger filter rack designed for bigger filters.
These large filters are often installed in the attic and should only need changing twice a year. I recommend checking with the manufacturer and your HVAC professional to ensure that your system can handle the extra load.
They significantly help improve indoor air quality and keep dirt from getting into the evaporator coils.
FAQs
How much does it cost to clean AC coils professionally?
The cost to clean AC coils varies dramatically by location and even between companies. On average, you can expect to pay $70-$150.
Is it OK to spray water on your air conditioner?
The outdoor unit is designed to get wet, so spraying water on it certainly won't hurt. Be careful when spraying the condenser coils, though, as the fins are easily bent. To avoid damaging the coils, be sure to rinse off any cleaners and debris.
What happens if you don’t clean your air conditioner?
A dirty air conditioner can cause a few problems. First, it loses efficiency due to the caked-on dirt. That means the home won't be as cold, and it will take longer to cool off. Even worse is the high electric bill.
However, a dirty air conditioner can lead to poor indoor air quality and create an ideal breeding ground for mold growth.
Can I pressure wash my air conditioner?
I always advise against using a pressure washer to clean an air conditioner. The high water pressure can easily bend fins, causing permanent damage. Bent fins lead to lower airflow over the coils. The only way to straighten them is with a fin comb, and they are never perfect again.
Does cleaning the AC make it cooler?
Cleaning an air conditioner doesn’t always improve cooling. However, it can improve airflow in both the evaporator and condenser coils. The added airflow helps improve energy efficiency and cooling efficiency.
