How to Clean an A/C

During my day job, I work for a weatherization company. I audit and assess houses to determine what we can and can’t do. I help people save money on their electric and/or gas bills.

In August, my air conditioner went out. First it was blowing hot air, and then it stopped altogether. I have had service/repairmen out to the ranch before and no one told me I needed to clean a little seen filter. I always clean the coils by softly vacuuming the top, and I always change the filter, but I never knew there was a location under the coils that gathers mold, dirt and mildew. Needless to say after six year of not cleaning it was pure black and two to three inches of caked on dirt and hair. I have cats and dogs that come in and out of the house, not to mention I live on a dirt road.

I talked with one of our contractors about the dilemma. He said I could call a service repairman and let him clean the coils and the underside of the air conditioner, as well as the outside unit filter for $300 to $500, or do it myself. I opted for clean it myself.

First of all, I had no clue that the pretty lattice work on the outside of the outside unit actually protected a filter. That filter also has to be cleaned at least monthly. The outside filter was easy – remove the top metal protector, and then, using a spray nozzle, gently spray the inside of the unit. Another tip is to be sure your unit is on a level cement pad. The level pad keeps the coolant circulating to all the important parts of the unit. You can also use the safe-for-pets (no acid) cleaning solution that is used on the inside of the a/c inside your home. Initially, I bought foam cleaner that you can buy at any box store. The foam cleaner may work if you do not have six years of build up. The heavy duty cost me less in the long run and proved more efficient. You can buy these from an air conditioning outlet store that also sells to consumers.

Second, I moved to the underneath coils inside the house. The crawl space is very small but I can fit in it, although at one point paying someone $500 for the cleaning was mighty tempting. For this chore, I bought a metal pan for the dirty water and excess hair/grit/dirt to collect in as I cleaned. I bought clear goggles to protect my eyes, long plastic gloves to protect my hands (and nails), and a soft metal brush. Since I couldn’t find one that I liked, I used a spike, but soft, hair brush. I also bought a small wet vac to vacuum up the “mud” that I cleaned off the inside coils.

I gathered my tools together, along with a spray bottle for the solution (the less you dilute the quicker the job progresses), and I had a flashlight handy. I waited for the right day as I knew it would take me hours, if not all day. I CUT OFF electricity to the house. I didn’t want to take a chance of damaging the unit or air conditioner motor, much less electrocute myself.

I finally crawled under the crawl space of the coils to assess the task at hand. I estimated three hours but it took me all day just on the inside unit. With my mixed solution in hand, I sprayed and gently wiped; no luck. I then decided to mix a heavier solution to water ratio, spray or pour it on the area, and let it sit for a few minutes. Bingo! That worked. I covered a few inches at a time until I thought it was clean. NOTE: When you clean the coils do so gently – go with the coil vent versus against the “grain”. You do not want the delicate vents to bend – and they will if you are not careful.

I went back to work the following Monday and proudly proclaimed I thought I had it clean. Wrong, I wasn’t done.

The next day, I got home, got the trusty flashlight and placed it in a bucket under the coils. I looked from the topside and there were still some locations that the light did not shine through. I went back to work. Once I could see all areas of the light through the coils, I was finished, almost.

I hooked up my trusty vacuum cleaner with the soft brushes, and vacuumed inside the air vents of the house. I also washed the air vents for an added measure. I bought silicone spray to spray on the copper joints as this will prevent rusting and ensure a long life for your unit.

Given the hectic time it takes to clean up an ac, I might as well consider looking for a smaller and cheaper brand like the blaux portable air conditioner as it is affordable and lasts for a longer period with nice cooling effects in the bargain unlike some bigger ones but that is a discussion for another day.

How often you clean is up to you. However, if you live in the country, or live where there are many allergens, dirt and you have pets, clean it as often as you need to. With my furry children, that is every four months!