How to clean an AC filter – whether yours is wall mounted or portable

Here's how to clean an AC filter, according to HVAC experts

orange sofa in dark green living room with air conditioning unit
(Image credit: Getty images / onurdongel)

You're going to need to learn how to clean an AC filter whether you have a portable or installed cooling system. Air conditioning is a lifesaver in hot climates – and as the world is getting hotter and hotter, we need our AC units more than ever, in our homes and workplaces. Air conditioning is the only way to cool down a space effectively when temperatures hit extreme levels – especially when there's no respite from the heat at night. 

So, AC units are irreplaceable for keeping a house cool in summer. However, their efficiency in cooling air can come at the cost of poor air quality if they aren't maintained properly. AC units need regular cleaning and that includes removing the filter for either cleaning or replacement (more on that below). If you want to DIY clean your AC filter, here's how to do it, according to HVAC experts. 

How to clean an AC filter

As Walter Bennett, AC expert at Green Leaf Air, explains, 'if your AC is not performing to its best, it might be due to dirty filters. Cleaning the filters can help your unit run smoothly and more efficiently.' To clean your AC filter:

1. Turn off the power to the AC by unplugging it from the wall. 

2. Remove the cover from the AC unit. 

3. Disconnect all of the cords to cut off electricity supply. 

4. Remove any pieces of debris that may be blocking any of the vents or filters. 

5. Clean all the vents and filters on the AC unit with a vacuum cleaner and removeable parts with a water spray bottle. Be sure to rinse everything off afterwards.

6. Replace all of the parts, including the cover, and reattach all the cords.

It's important to clarify that you should only attempt to clean a mini-split AC unit filter. Lane Dixon, Vice President of Operations, Aire Serv, a Neighborly company, tells us that 'with traditional HVAC units, you don't want to clean the air conditioner filter; you should replace it periodically.'

However, if you have a mini-split unit, you can clean it yourself: 'open the front casing of the mini-split, remove the filter and vacuum it until it is free of dust and debris.'

How do you clean a portable AC?

If you have a portable air conditioner, you'll still need to clean the filter every once in a while to make sure it's running properly. Bennett recommends the following step by step method:

  • Access the filter: it 'is usually located on the back or side of the unit.'
  • Remove any debris or dust with a brush or vacuum cleaner. If the filter becomes clogged, you may need to replace it. 
  • Wipe down the exterior casing and filters with a soft cloth. Use a mild cleaner, such as 409 spray cleaner or window washer fluid, if necessary. Don't use harsh chemicals, as this could damage the machine. 
  • Rinse off the exterior casing and filters with clean water and blot dry with a cloth before replacing any parts that have been cleaned. 
  • Allow it to air dry for at least 30 minutes before using it again.

Can you clean an AC filter and reuse it?

Dixon stresses that he doesn't recommend reusing AC filters – getting a replacement is always preferable. Having said that, 'if you notice your HVAC filter is dirty and you don't have one to change it out at the moment, you can run a shop vacuum with high suction over the filter fibers to clear dust and debris from the fibers until you have time to purchase a new filter.'

Can an AC filter be washed?

Again, this completely depends on whether you have a mini-split or a traditional AC unit. Dixon says: 'You can hand wash plastic mini-split filters, but you should not have to wash them. Once you have taken a shop vacuum to the mini-split filters, you can go over them with a microfiber cloth for additional cleaning. You can't wash traditional HVAC filters as they are not made of a washable material.'

How often should an AC filter be cleaned?

If you have the type of AC filter that can be cleaned, then you should clean it every six months or so. Bennett advises: 'AC filters should be cleaned on a regular basis to ensure efficient operation. Every three to six months, an AC filter should be cleaned according to the manufacturer's instructions. Dirty filters can cause poor air quality and even damage your AC unit.'

Have a traditional AC unit? Dixon recommends replacing the filter 'a minimum of every 90 days. This varies depending on specific conditions within each home and type of filter.'

If you're not sure what type of AC unit you have in your home, call out a HVAC professional – they'll be able to advise and/or do the job for you.

More about our AC advisors

Walter Bennett

Walter is Dallas TX based HVAC design and IAQ expert for homes and multi-storied buildings. He is working for Green Leaf Air, which handles intricate HVAC design, air duct cleaning, ac unit installation, etc., in homes, offices, and commercial spaces all over Texas.

Lane Dixon, Vice President of Operations, Aire Serv Heating & Air Conditioning at Neighborly
Lane Dixon

Lane Dixon is Vice President of Operations, Aire Serv, a Neighborly company, which specializes in heating and air conditioning. Aire Serve is based in Tennessee. 

Anna is a professional writer with many years of experience. She has a passion for contemporary home decor and gardening. She covers a range of topics, from practical advice to interior and garden design.