how to clean air conditioner filter

When you get a new air conditioner, it performs at its best, cools rapidly, and is highly efficient. However, as the system is used and ages, the efficiency and cooling abilities dwindle. The good news is there are things you can do to help your AC system.

This article will go over all of the maintenance and upkeep procedures for your type of air conditioner. We cover cleaning and maintenance by AC type and parts, plus we cover some basic tools and usage, too.

Benefits of Regular AC Maintenance

As you can probably assume, there are many benefits to keeping your AC system clean and well maintained. However, there are a few reasons you may not be aware of.

Improves airflow.
Clean intake and exhaust vents, as well as filters, keep the circulation and airflow high.
Maintains efficiency.
A clean system performs better and will run more efficiently.
Prevents mold and mildew.
Proper cleaning removes the possibility for mold spores to flourish.
Makes colder air.
A clean and adequately operational HVAC system can produce colder, cleaner air.
Prevents bad odors.
Cleaning your air conditioner properly will help remove and prevent unwanted smells and odors.
Prolong the life of the system.
An air conditioner running correctly and cleanly will last much longer than a dirty, overworked unit.

As you can see, there are plenty of reasons to have a cleaning and maintenance routine for your AC. However, it doesn't end there. Staying healthy, breathing clean, cool air, filtering out allergens and particles in the atmosphere of your home, and saving money are all excellent reasons to maintain your system.

General Steps to Cleaning the Inside of a Central AC Unit

Cleaning your air conditioner requires a little bit of knowledge. You will need to remove access panels or take apart the housings (depending on the type of AC). You also need to understand electricity and the use of cleaning chemicals.

Safety First

There are two main risks involved in cleaning your AC. Electricity can shock, burn and, in serious cases, kill. It is vital to turn the system off and remove all power sources. For portable and window units, you can turn the switch off at the control panel and unplug the unit from the outlet.

For central and mini-split systems, you will need to turn the system off at the thermostat, and turn off circuit breakers or remove shut-off switches. No portion of the system should have power at all.

You also want to watch out for refrigerants. Leaks can be high pressure enough to lance skin, and the refrigerant itself can cause frostbite and the loss of fingers. After the machine is powered off, make sure you don't hear any leaking, see bubbles from refrigerant lines, and that the coils are not frozen or the high-pressure line too hot.

Preparing the Tools Needed for Cleaning

Before you go any further, it is best practice to have all of your tools and equipment nearby and at the ready.

Screwdrivers and bolt removers are needed to disassemble the compressor and fan shrouds. You will also need a fin brush or straightener, a water hose with a low-pressure setting nozzle, and other items.

If you have never cleaned or taken apart an AC unit before, you should brush up on the process by reading the owner's manual. If you do not have the owner's manual anymore, you can usually find one online by searching for your brand and model number.

Once you are familiar with the process, have the tools ready to go and the power supply cut off, it is time to clean.

Removing Dirt & Debris from Outside Unit

You always want to clean from the top down. When it comes to the outside unit or condenser, you will do this at least twice.

First, you will want to unscrew the screws holding in the fan and condenser cover. These will be the screws along the top edge of the entire unit. Place them in a labeled bag or magnetic bowl so you don't lose them. Lift the fan and cover (as one unit) up and tilt it out of the way.

The wires going to the fan will prevent you from removing it completely, which is okay. Using your garden hose, you want to spray the outside of the unit from top to bottom on all sides. Once the dirt, leaves, and pine needles are washed away from the outside, repeat the process from the inside.

There is a small drain hole at the bottom of the unit, though it will probably be filled with leaves or mud. With a gloved hand, find the hole and clean it out so the water can drain from the unit. Continue to spray until all of the mud, dirt, and debris are washed away from the condenser.

If you notice any bent fins over the coils, you can use your fin brush to clean and straighten them. Spray once more to ensure all the dirt is free from between the fins and coils on both sides, and then place the fan and cover back on. Secure it in place with the screws.

Disassemble the AC before Cleaning

For portable models, window or through-the-wall units, it is much easier to disassemble the unit before you start cleaning. This entails finding the case screws, removing them, and pulling the clamshell off the main body.

For window units, there are usually two screws on each side, 2 to 4 screws on the back lip of the casing, and possibly a few under the front faceplate.

Once the shells are off, you will have full access to the internal parts where you can wipe, spray, vacuum, and clean as needed. It is possible to clean the units without taking them apart, but this process is much more delicate, requires more tools and isn't as thorough.

However, if you can't remove the case or just don't want to, you can use canned air to looses dirt and debris and a vacuum hose with a bristle brush to remove most of it.

Cleaning Each Component

Each piece inside the AC has a specific cleaning regimen. For example, you cannot clean the filter the same way you clean the condenser coils. Below you will find more detailed instructions for each piece.

As long as you realize there isn't a one-size-fits-all cleaning tool or method, you will have the upper hand. Expect to get dirty and wet and protect yourself by wearing latex or rubber gloves and eye protection.

Proper Re-Assembly

Once the unit and all internal pieces are clean, you can reassemble the unit. Ensure each screw aligns with its threaded hole and tighten just enough to catch until all screws are in place.

Go back through the sequence and tighten everything down after you have verified alignment and that all wires, coils, fins, and power cables are out of the way. After the screws are tight and the unit is back in place, plug it in, restore power to the circuit, and test the unit out for proper operation.

Cleaning Central Air Conditioners (By Parts)

As mentioned above, cleaning each part of an AC unit takes a different tool and different method. Below, you will find those methods outlined in more detail.

Condenser/Condensing Unit

Cleaning the condenser and condenser unit is best done as outlined above. However, there are a few instances when a garden hose and fin brush aren't enough. If the debris and dirt are too hard to remove and are clogging the find, there is another method you can utilize to get them clean.

The best option is to use a propane torch. Propane will burn hot enough to melt away any grime, debris, leaves, and other stuck-on messes from the fins and coils. But unlike MAP gas or an acetylene torch, it doesn't burn so hot that it can damage the unit.

Just make sure the torch stays away from the wiring, compressor, fan motor, and electrical panel. You will want to use slow, sweeping motions from top to bottom until the debris is burned away. After the coils and fins have cooled down, rinse clean with the garden hose.

Filters

Cleaning the filter will depend on the type of AC and the type of filter. Central and mini-split systems mainly use paper filters with 30 to 90-day replaceable filters. These do not need to be cleaned. Instead, you just buy a new one and replace it.

For portable units and window ACs, washable filters are the more common application. These are screen or mesh filters that can be brushed, washed, or rinsed off. Ensure that the system is off while the filter is removed, or your cleaning will be pointless.

Evaporator

The evaporator unit takes the warm air from the intake passes over the evaporator coils where the air is chilled, and the blower motor sends it through the ducting to your individual rooms. The evaporator is arguably the most difficult to clean. It has direct 220/2240 volt wiring, heating elements, fins and coils, plus fans and motors.

Locating the unit isn't always easy, and access is usually more than just a couple of screws. However, once the access panel is located and opened, you should be able to access the coil area with some ease.

The use of a coil cleaning solution is ideal here. You can spray the coil cleaner on the fins and coils, allow it to set, penetrate and dissipate, then rinse it off. The one thing to make note of is the drain pan.

If the drain pan drain becomes clogged, the water and cleaner won't have anywhere to go. If the drain pan overflows, you will have a much larger mess to deal with. Before you start cleaning the evaporator, slowly pour near-boiling water mixed with a little vinegar into the drain pan. If the drain is clear, the water will drain quickly. Otherwise, you will need to clean out the pan first.

Coils

Evaporator and condenser coils may look similar. They are designed to work in tandem and of the same capacity. This means that the evaporator's coils will only absorb as much heat as the coils in the condenser can release.

Copper tubing is the primary coil material and needs to be kept clean to allow as much heat transfer from the air as possible. Coil cleaner solutions are best suited for this as they will break down dust and debris build-up while not leaving residue behind.

You will need to spray the cleaner onto the coils and allow it to set (usually 5 to 15 minutes) as it cleans the dirt and debris are dropped into the drain pan. Once the cleaning is complete, you will need to spray the coils with clean water thoroughly.

Fins

The fins, usually aluminum, surround the copper tubes of the coils. The aluminum helps disperse the heat for easier absorption (evaporator) or release (condenser). The fins need to be cleaned, and coil cleaner will work for the fins as well.

However, there is an additional step needed for the fins. You need to ensure the fins are straight, inline and not bent, kinked, or broken. To do this, you will need to run a fin comb through the fins. This will help clean them but also works to straighten them out and lift any that have fallen over.

Condensate Drains/Drain Pan

The drain pan is crucial to the overall operation of the evaporator. Its primary duty is to collect the condensate that forms on the coils and remove it from the home. This lowers the overall humidity of the air in your home and removes excess moisture.

Secondary, though, it also collects dirt, dust, and debris. Over time this can build up in the pan itself or, even worse, in the drain line. When cleaning the evaporator, you must clean out the drain pan. Usually, the pan has limited access and cannot be removed.

You can pour hot water to help loosen the build-up, but a scraper, vacuum (that can also clean up wet messes, such as a Shop-Vac) is ideal. After the pan is clean, placing a few drain pan tablets into the pan will help prevent build up in the future and make the next cleaning cycle easier.

Ducts & Vents

Cleaning the vents is done by removing the screws that hold them in place and washing or vacuuming them off. You can also vacuum out the ducting as far as your vacuum hose will reach, but there isn't much need to go further.

Duct cleaning is one of those AC parts that is debated whether it should ever be cleaned or not. However, a clean duct is never a bad thing.

If you have just purchased the home or moved in after it has been vacant or dormant for more than a year or two, then a professional duct cleaning may be needed. Likewise, if you have a musty, mildew, or smoldering odor when running your unit, duct cleaning may be helpful.

Otherwise, the cycling of air, both cold and hot, moving in the ducts through the seasons is enough to keep them maintained.

Common AC Cleaning Problems for Homeowners

Sometimes there are situations or access problems that prevent normal cleaning methods. Let's take a look at some of those problems now and see how to overcome them.

How to Clean the Outside of an AC Unit

Just like the interior of your AC unit, the outside can become covered in dust, dirt, and debris. While this may not always hinder the AC's performance, it isn't good to have that build up mixing with the air you breathe.

The outside unit, or condensing unit, can be sprayed off with a garden hose. Ensure you spray the fins head-on instead of from the side to prevent fin bending or damage.

For the inside unit or evaporator unit, you will need to use some elbow grease. Mixing a small amount of dish detergent with warm water will eliminate most dirt and dust build-up and remove any smoke or nicotine residue.

How to Clean a Window AC Unit without Removing it

Some window units are too heavy to remove from the window just for a little cleaning. If you cannot remove the unit, you can still perform some cleaning to help the AC perform better.

The filter should be removed and cleaned as needed, but you can pop off the front faceplate to access the front of the evaporator coils and ducting. Protect your floor with a drop cloth or towel and use coil cleaner on the coils.

You can use a spray bottle of warm water to rinse as needed and wipe it down with a dry cloth to finish. While the faceplate is off, you can clean both sides of it as well as the vents and ducts. Replace the faceplate and filter, ensuring both are completely dry before plugging the unit back in.

How to Clean a Portable AC

Many small portable ACs are not designed to be taken apart. Some of the screws may be hidden, positioned under warranty void stickers, or require a special tool to remove.

In these cases, you can use a vacuum to clean out the vents and air intake areas. Wipe down the entire unit with a damp cloth and use smaller tools like cotton swabs or a butter knife to loosen stuck-on dirt or debris.

If your model has a drain pan, bucket, or hose, you can remove these and clean as needed in the sink or tub. The filters, if equipped, can also be removed and cleaned.

How to Clean an AC Unit with Heat Pump

Cleaning a heat pump is the same as cleaning a condensing unit. You will want to remove the fan shroud and cover, as well as the case. Once exposed, you can spray down the unit with a garden hose, being careful not to bend the aluminum fins.

Once you have removed all the leaves, debris, dirt, and dust, you can reassemble the case and fan shroud before restoring power to the unit and letting it run.

Tools & Materials Required for AC Cleaning

Surprisingly, cleaning an AC doesn't require a lot of equipment. Below are the standard tools and items needed. Your particular setup, model, or installation location may require more, though.

Screwdrivers.
You will need a flat head and Phillips screwdriver. It is also wise to purchase a multi-tool screwdriver with different side bits. The hexagonal drives will also fit the condenser screws.
Dropcloth or towels.
Cleaning your AC isn't the driest chore you have. Using a drop cloth or towels will protect your floors from water draining or overflow and make cleaning up after yourself much easier.
Latex or rubber gloves.
Some of the materials and solvents used can dry out your skin or cause irritation. It is better to protect them with some gloves.
Eye protection.
Water and cleanser spray as well as flying or falling dust and debris can quickly get into your eyes. Safety glasses will protect your vision.
Coil cleaner.
This spray comes in cans and is relatively inexpensive. A single can of spray will usually be enough for multiple applications.
Garden hose and nozzle.
Spraying off the coils on the condenser unit is best done with a garden hose with a soft spray to avoid bending fins.
AC fin comb.
A fin comb is used to clean and straighten condenser and evaporator fins. You will want to choose a comb that has multiple comb heads since fins are not universally spaced.
Wire brush.
A small wire brush will allow you to clean the copper coils or condensing unit shell if needed.
Propane torch.
If you need to burn the coils and fins clean, using propane is the safest option without causing heat damage.

Additional Tips in Keeping ACs Clean & Well-Maintained

Regular cleaning and maintenance will be your biggest ally in keeping your AC unit performing at its best. However, there are other things you can do to help minimize the cleaning and increase AC performance.

Don't smoke indoors.
Smoke leaves a sticky residue on the internal components, attracting dust and dirt, eventually building up to a larger problem.
Maintain the cleanliness of your home.
Vacuuming your floors and keeping dust and dander to a minimum will help the filters control the rest, keeping dirt and debris from entering your AC system.
Run only when needed.
Constant use of your AC can cause more wear and tear on the compressor and fans. As they age, they will not perform as well.
Supplement with fans.
Using oscillating floor fans or ceiling fans will help the system run more efficiently.
Replace filters in a timely manner.
Clogged filters and old filters prevent proper airflow and will cause the system to work hard and run longer.

Conclusion

Keeping your AC unit clean, well maintained, and in good working order has a lot of advantages. While it can be a lengthy and cumbersome chore, it is essential to top performance and efficiency.

This article showed you all the tools and procedures you need for cleaning your HVAC system, portable and window AC units. You should be better equipped to handle the chore now and do so with confidence.

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Ian Haynes is an HVAC writer, and researcher. He has worked on hundreds of articles relating to home cooling, heating and air quality with a vast knowledge of the technical aspects of these types of appliances. Outside of his work, Ian likes exploring Brooklyn with his Labrador. Learn more about the AC Lab team here.