Maintaining your air conditioner (AC) is essential in ensuring that it runs well and lasts as it should. Having professionals conducting yearly inspections can help spot minor issues before it requires significant repairs.

In some cases, you might need to perform essential maintenance works by yourself to save on costs or time. This article covers the basic information about the AC and how homeowners like you can ensure its efficiency through a definitive checklist below.   

Checking potential issues like leaks and cleaning some of the primary components like the insulator and drains are simple. However, you must understand how your air conditioning system works before performing any of these tasks. 

Understanding how the air conditioning system works 

Air exchanger info

You all know the air conditioning system to be responsible for cooling us down when temperatures soar. But how does the machine do that? Generally speaking, an AC sucks in warm air from the surroundings and releases it outside your room. This holds regardless of the type of system you have.  

The following essential air conditioner parts work together to manage temperature and give you comfort:  

  • Refrigerant: This cooling mechanism goes through the tubes and is responsible for collecting heat and redirecting it outside. The compressor drives its movement. 
  • Compressor: This section is responsible for converting low-pressure to high-pressure vapor to pump the refrigerant, making it one of the most critical parts of the AC system. 
  • Condenser: The refrigerant passes through the condenser after being released from the compressor. Condensing coils cool the hot vapor and turn it into a liquid with the help of a fan. The liquid is then carried toward the expansion valve. 
  • Expansion valve: Gas expands as it cools, and this is what happens as the refrigerant passes through it. This process is responsible for cooling the room and eliminating heat.  
  • Evaporator coil: Warm air from indoors passes the evaporator coil, which also carries the refrigerant that cools the air in the evaporator. This cooled vapor is then distributed via ductwork while the warm air passes through the compressor, moving toward the condensing unit located outside your home, then gets cooled again in a repeated cycle.

After getting an idea of how your AC works, it’s time to identify the sections you can check and clean to improve your unit’s performance and lifespan. 

Keep your outdoor condensing unit and its surroundings clean      

The condensing unit is located outside the home, and it’s vulnerable to being soiled or collecting dust. When this happens, your AC unit’s airflow is impeded and interferes with the coil’s ability to process heat, reducing your appliance’s efficiency. As much as possible, remove plants and cut the stems or leaves growing close to your condenser to ensure air flows smoothly. It would also help if you could check the evaporator coil and remove dust and other debris, at least once every year.

Read more: Planting around AC unit

Clean your condenser 

If you notice dirt collecting around your outdoor condenser, consider removing it by cleaning the unit. After turning off the power source and keeping the surroundings clear of debris, wash the unit using a garden hose. For more thorough cleaning, though, seek the services of heating, ventilation, and air conditioning (HVAC) professionals, as the task may require you to remove parts and reassemble them.  

Fix and clean coil fins 

After washing your condenser unit, check whether the coil fins located on the condenser and evaporator coils are deformed or have dirt in between them. Depending on the damage, use a fin comb to restore its condition. If you don’t have this tool, get a knife and slowly insert it to do the job. Don’t insert too deeply, or you’ll risk damaging the unit. For dust collecting in between the coil fins, use a brush and cleanser.

Check your air filter 

air filters on DIY Air Conditioner Maintenance Checklist

An air conditioning filter works by preventing the entry of pollutants, dirt, debris, pollen, and other small particles which can spread through the air ducts. Filters can be reusable or disposable. It’s recommended to replace or clean the air filter once a month or every two months, depending on the season and whether you have pets or allergies.

Filters are located differently, depending on your AC unit. For instance, window-mounted units have filters in front. For centralized ACs, it may be located along the return ducts, while other filters are positioned in walls or ceilings.  

Clean or replace your air filter  

Some air filters can be removed and washed. But first, tap off the dust then gently wash the front and back sections. You can just let tap water run through. If there’s persistent dirt, wash the filter with warm soapy water and lightly scrub with foam.   

Keeping your air filter clean can easily ensure your unit’s efficiency. According to estimates, dirty and blocked filters can increase energy consumption by up to 15%. That’s because it can impede airflow and dramatically reduce system performance. Obstructions can harm the evaporator coil and reduce its capacity to process heat.  

Check the room for leaks and seal them 

There are a few ways to locate air leaks, one of which is holding up incense or toilet paper in areas where there might be a leak. An erratic smoke or paper movement will indicate your suspicion. In addition, check your window frame and doors, and ensure there are no loose connections.

Use caulk to seal smaller gaps and an expandable foam spray to seal sections with bigger openings. Doing this can also ensure efficiency and help extend your unit’s lifespan. 

Need help getting your home maintenance checklist right?

Check and unclog drain tubes 

house ventilation

Blocked drain channels hamper the AC’s capacity to manage humidity. If your AC is running, and you notice water pooling near the furnace, it can be an indication of obstructions in the condensate drain tube. These blockages may be from slime that plugs the pan drain tube. Purchase pan tablets and insert them into the drain opening. Use a screwdriver to push them farther into the unit. Otherwise, install new tubing.

Read more: Prepare HVAC for home renovation


The points discussed above cover the basic maintenance works homeowners like you can perform while waiting for your HVAC professionals. However, if you notice any issues while using your cooling appliance, check the parts mentioned above for a quick fix.

If the problem persists, and your AC can no longer manage to cool you down, it’s better to hire HVAC experts to make the necessary repairs.       

DIY air conditioner maintenance checklist was last modified: September 7th, 2023 by Billy Guteng
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How bad would it be if you’ve kept an air conditioner clogged with debris for like half a year?