We recently had an air conditioning unit repaired. When had done the job, the guy asked when the last time was that we had our units serviced, and looked shocked when we said we never service them; all we do is clean out the dust filters. He says we should service them at least once a year, otherwise parts are liable to get damaged. Of course, the fee is no small amount; it's a significant percentage of the cost of the unit itself, and we have 8 units in the house.

We've had our units for several years, and none of them have ever been serviced, nor have they ever broken down for lack of servicing. Have we just been lucky, or is there no real need to service these things?

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    Refrigerant levels is all I can think of. If it's too much, then the original installer didn't do his/her job, and this should only need to be fixed once. If too little, then again install fault, or a leak. If anything needs to be done regularly... there's a leak, and just adding more is dumb. May 2, 2016 at 10:01
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    The airfilter, of course, should be checked and cleaned or replaced annually or more often if you live in a high-particulate area. The rest of the system doesn't require much maintenance. It's far cheaper to pay for a repair call if the coolant leaks out or a pump dies than to pay the rather large "service call" fee every year. May 2, 2016 at 12:51
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    Are these central, mini-split, or window units? May 2, 2016 at 14:02
  • @DanielGriscom: split units
    – Shaul Behr
    May 2, 2016 at 14:07
  • @CarlWitthoft are you sure about that? Some companies offer annual service for a fair price. If you can get an extra 10 years out of your equipment with regular maintenance, isn't it worth it?
    – Tester101
    May 2, 2016 at 14:10

2 Answers 2


Annual maintenance is recommended by the manufacturers, and installers of the systems. The majority of the maintenance time, will be spent on cleaning the unit. Keeping the unit clean will help keep it running more efficiently, and can increase the life of the unit.

The technician will inspect the unit to ensure it's still in good condition, and will look for parts that may be near the end of their life. Replacing parts before they fail can save you the headache of replacing them when they fail (which will surely be on the hottest day of the year). Replacing parts before they fail can also help prevent damage to other parts of the unit.

Depending on which company does the service, they may actually measure the amount of cooling the system is providing. They may also check for refrigerant leaks in the system, but likely only if the refrigerant level is low. If you have any questions or concerns, they'll likely address those at this time.

While these units can run trouble free for many years without maintenance, keeping them clean and in good repair can save you money and reduce the chances of a failure. Of course you can do some of the work yourself, but often it's easier to pay somebody else to do it.


Your experience might be different. We have 3 Mitsubishi units and a HRV system. The installer (registered by Mitsubishi) has been servicing them annually, and the fee has been going up every year.

So, the last time I followed him around and noticed that all he did was clean the filters. I confirmed with him that that is all he does. So I am going to do that myself from now on, while I find a company that will actually service them.

I think they should be serviced, but make sure they are actually serviced. Which is not just cleaning the filters, but also testing their operation.

I just found a local crowd advertising that they do the following for servicing

Indoor Unit

  • Check & tighten electrical terminals
  • Check temperature output readings
  • Clean & disinfect coils
  • Clean air filters
  • Check condensate drain
  • Check noise level of fan motor
  • Clean unit case
  • Check system fault diagnostics

Outdoor Unit

  • Check refrigerant gas pressures
  • Check electrical current draw
  • Check & tighten electrical terminal
  • Check noise level of fan motor
  • Check noise level of compressor
  • Clean coils
  • Check condensate drain
  • Check unit is level
  • Clean unit case
  • Even with filters, some dust can build up on the fins and fan, the condensate catch basin and drain and pump if you have one) can develop mold or clog problems, pumps and motors and valves can eventually start to fail... The list you show does seem to cover the likely issues. The are videos on the net covering some of that if you want to DIY. Be aware that the thin aluminum fins are easy to damage if you aren't careful, which would impact performance... And that maintenance by untrained individuals may void your warranty if they do botch something.
    – keshlam
    Aug 11, 2023 at 12:26
  • FWIW, the same installer sold my neighbor a service contract and didn't even offer one to me. Then again they sold her the smart-home interfaces and didn't mention those to me, so the salescritter may just have decided I was too cost-sensitive.
    – keshlam
    Aug 11, 2023 at 12:31

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