How To Clean Out Central Air Conditioner

Dan has been in the HVAC industry for 23 years with experience ranging from installation and service to sales and distribution.

Here comes the sun...and heat.

J.S. Matthews

Cleaning Your Air Conditioner Increases Efficiency

We long for that summer sun to shine down so we can get outside to enjoy the day but when the day is done and it's time to come in. Oh, and fire up the A/C because no one wants to sweat inside.

Like so many other things, our air conditioners need to be serviced. Often the repair and maintenance costs related to furnaces and air conditioners are not cheap. Well here is a step-by-step guide to preparing your air conditioner for the upcoming heat. It's free, it's simple and it can help to keep your air conditioner running efficiently which we all know can save us money.

Chillin' With Your A/C

Things You'll Need to Clean Your Air Conditioner

There are many items needed to do this job and you likely have them in your house already.

Hex Head Nut Driver (Size may vary, see photo)
Towel
Hose (hooked up to running water of course)
1 cup of Simple Green (or similar cleaning product)
Air filter (size will vary)

4 Steps to a Clean Air Conditioner

Disconnect the power.
Remove the top of the air conditioning unit.
Start cleaning the air conditioner.
Change the air filter and clean the drain.

1. Disconnect the Power

As always the first thing we want to do when working on HVAC equipment is making sure that the power is off. Most air conditioners have a service disconnect mounted to the home within a few feet of the condenser (the condenser is the part of your air conditioning system that is located outside).

When you open the lid on this disconnect there should be a handle that can be pulled out and in turn, disconnects the power supply to the air conditioner. Once you have removed the handle, make sure to shut the lid on the disconnect. Note that I said it disconnects power to the unit...not the disconnect. The incoming power here is still live and you do not want to spray this with the door open.

If you want to be extra safe or do not have a disconnect, locate the breaker in your electrical panel that is dedicated to the A/C system and shut it down.

Condensing Unit (or Air Conditioner Unit)

2. Remove the Top of the Air Conditioning Unit

Now that the power is off, use your hex head nut drivers to remove the bolts that are mounted around the top of the unit. Once these bolts are removed, the whole top will be able to be lifted off of the condenser along with the fan and motor. Do not remove the bolts that hold the fan and motor to the lid.

There will also still be wires attached from the motor to the service panel on the side of the unit. Leave these wires attached as I do not want to involve you with any of the electrical components in the service area. You should have enough slack that you can swing the lid off to the side and set it up so that the wires are not stressed or rubbing on anything sharp.

NOTE: While performing this maintenance, it is important not to smash the fins that are wrapped around the condensing unit. These fins allow air to be pulled into the condenser. If smashed or clogged, the air cannot pass over the coils and compressor fluidly and will decrease efficiency and potentially cause the unit to overheat. If you do smash a few or a few were already smashed, they do sell combs for opening back up these fins. If you do not have a comb, others items may suffice in opening them back up with a little extra time and care.

Spray water from the inside of the towards the outside.

Remove any leaves or other debris inside the unit. This will help prevent corrosion and increase air flow.

Spray water from the inside of the towards the outside.

3. Start Cleaning That A/C

With the lid removed you should now be able to easily access the inside of the condensing unit. Start cleaning by removing any debris (leaves, "helicopters", etc...) in or out of the unit that can be removed by hand. This will keep water from being trapped under leaves and such that lead to the eventual rust and breakdown of the unit's structure. Now, place a towel over the service panel area. This will not prevent all water from entering the panel but can help to catch a fair amount.

Now spray away. That's right, spray your hose from the inside out in the unit. Remember, the air is being pulled into the unit thus spraying from the outside-in only forces the dirt deeper into the fins. There is no need to worry about the water. These units are made to be outside so nothing you're doing here is anything nature hasn't done already. Just be sure of a couple of things.

Don't have the pressure set so high that it bends the fins around the unit.
Do your best not to spray directly into the service panel area or at the service disconnect. Again, I'm not too worried about these items as they are rained on regularly but there's no reason to test their limits.

Once you're done spraying out the dirt, you should be able to look through the fins or brushes and see daylight. That's it. Remount the lid to the air conditioner's condensing unit as it was and bolt it down.

For an even more in-depth guide on cleaning the coils of your air conditioner, have a look at my guide How to Clean Air Conditioner Coils (with Pictures).

4. Change the Air Filter and Clean the Drain

Spring is a great time to replace that air filter. After being cooped up all winter with the dust and pet hair, it is likely that this is the time of year your filter is the dirtiest. Air conditioning is very finicky and sensitive to airflow. If the filter is clogged, your fan will have to work much harder and the evaporator coil is likely to freeze solid. This is not good, causes a mess, and ultimately renders the A/C system useless.

Lastly, I like to clean my A/C drain every year. This is optional and doesn't necessarily affect the efficiency of the unit but nasty deposits do build up in this line which could lead to blockage. A cup full of Simple Green is what I use because it works and is environmentally safe.

A Few Departing Tid-Bits About Air Conditioning Systems

The evaporator coil is the second part of the split air conditioning system. This is the portion that is on top of your furnace. Here in the photo above, you can see that I have room between the furnace and evaporator coil.

If you have this as well and have the tools to create an access panel here, that is a good idea. Reaching into the bottom of this coil, you may be able to remove blockages from dirt and hair that may have gotten past the filter. (Again, being careful of the fins.) If this cannot be done with ease, then I suggest you contact a professional HVAC technician to check this for you.

I also 100% stress that you are not to interact with the refrigerant at all. If you've cleaned the unit and it seems to still not be operating properly, leave it to a professional to check the refrigerant charge in the system. This requires specialty equipment, is very dangerous and if caught without the proper certification, carries a very stiff fine and penalties. Potentially prison and tens of thousands of dollars courtesy of the EPA.

How Much Do You Know About Air Conditioning?

For each question, choose the best answer. The answer key is below.

Which of the following is NOT a refrigerant gas?
- r-22
- 410a
- HGH
- r-12
What term describes the cooling capacity of an A/C unit?
- Cubes
- CFM
- Tons
- Square Footage
How many times a year should you add refrigerant to your system?
- Once
- Twice
- Monthly
- None. Only if there's a leak and I've had it fixed.

Answer Key

HGH
Tons
None. Only if there's a leak and I've had it fixed.

This article is accurate and true to the best of the author's knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: My house is extremely dusty, I think it comes from the heating system. Can I clean my heating system my self?

Answer: I have another article on cleaning your ducts yourself. If you'd like to read it it may help. Note that it's a do it yourself process that makes things better but is not equal to a professional service.

Question: Our metal ductwork, installed in 99, has a black installation type material inside the metal work. Some of the main area going into the fan area is made completely with this material. Is this material a source of dust and dirt?

Answer: It can be yes. That's an acoustic lining or ductboard which I'm not a huge fan of but that's my personal opinion. It's widely used.

viorel on August 01, 2014:

Thank you for advice.

John-Rose from USA on October 28, 2012:

Even though summer is over this is something that I really need to work on. I'm glad that I stumbled on your Hub. It was tery useful. Thanks ~ John

Dan Reed (author) on July 25, 2012:

Thank you Peter. You're right, the basic concepts of air conditioning are the same in most models and types. I'm glad you found this information helpful.

Peter Geekie from Sittingbourne on July 25, 2012:

Dear cre8tor,

Thank you for a very informative and helpful article. In the UK we tend to have mobile A/C but the basics are similar.

Kind regards Peter

Dan Reed (author) on July 20, 2012:

@ The Engineer - Thank you kindly.

Dan Reed (author) on May 25, 2012:

Thank you Laura. FYI - An older unit that is stressed is more likely to break down. Even just shooting it with a hose will help if it's really dirty to keep it running cooler. Just a thought but do understand if you're going with new.

Laura Schneider from Minnesota, USA on May 25, 2012:

I agree with daughter of Maat--excellent hub, self-taken photos that clearly show exactly what you're talking about, clear instructions--especially the warnings about electricity (so important!) and where you can and can't get in trouble with it. My A/C unit is too old to bother cleaning; I just plain need a new one that's Energy Star Compliant. But, my mother's unit needs cleaning, and I'll follow all of your directions to the T. Cheers!

Melissa Flagg COA OSC from Rural Central Florida on March 16, 2012:

I will make sure to swing by and leave a comment with our outcome. If it works, it'll be nice to have a normal electric bill again AND a cool house. Living in Florida is tough on a/c units. So I'm hoping this will work, we just had it recharged I think 2 years ago, so I don't think that is the problem.

I'll keep you posted and thanks again!

Dan Reed (author) on March 16, 2012:

@ D.O.M. - Thank you very much. I'd love to hear back on how it goes for you so that I know my instructions came through clearly.

Melissa Flagg COA OSC from Rural Central Florida on March 16, 2012:

This was an excellent hub. Our A/C has been on the fritz and is running constantly during the day. WE change our filter monthly(we have MANY pets) but have never cleaned the outside unit.My husband and I are going to try this over the weekend. Thank you so much for this hub! Voted up, useful, interesting and SHARED!