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Mike Smith Heating & Air Conditioning, LLC Blog

Dirty Coils: What They Mean


Your air conditioner’s coils, the tubes that contain the refrigerant, have a lot of work to do. In fact, there are two separate jobs happening at different points in the loop of coils that the refrigerant runs through. And this work can only be accomplished if the coils are clean. What problems do dirty AC coils cause? How do they get dirty? Can you clean them yourself? We’ve got the answers for you.

The Two Jobs AC Coils Do

The indoor unit of your air conditioner contains the evaporator coils. In this portion of the system, the refrigerant is absorbing heat from your home, and in the process, it evaporates from a liquid into a gas. It continues to flow through the coils to the outdoor unit, which houses the condenser coils. This is where heat is released from the refrigerant with the help of a fan blowing air over the coils, and this causes the refrigerant to condense back into a liquid. It continues through the loop back into your home to absorb more heat.

What Happens When the Coils Are Dirty

Dirt acts as insulation, preventing the refrigerant from changing temperature as readily as it should. Dirt on the evaporator coils prevents the refrigerant from absorbing heat from your home, decreasing the cooling power of your air conditioner and driving your utility bills up. It can even cause ice to form on the coils, which adds another layer of insulation, making the problem even worse.

Dirt on the condenser coils prevents heat from being released, so the refrigerant doesn’t drop in temperature enough before it re-enters your home. This also decreases the AC’s cooling ability, and if this situation continues for too long, it can overheat the compressor in the outdoor unit. That’s really bad news. If your compressor fails, you’ll probably need to replace the whole air conditioner. 

Preventing AC Coils from Getting Dirty

Indoors, the main culprit is dust. Changing the air conditioner’s air filter frequently will cut down on dust. It should be changed (washed if it’s reusable or replaced if it’s disposable) every month while your AC unit is in frequent use and at least every three months when it’s being used less. Keeping the area around the unit clear of dust will also help. Outdoors, dirt, and debris are the most likely culprits. Don’t allow plants to grow right up against the outdoor unit, make sure fallen leaves are raked away, and protect it from mud splatters or gardening soil as best you can. 

Cleaning AC Coils

If there’s a bit of dust or dirt on your coils, there are some things you can do to remove it before it seriously impacts your air conditioner. Compressed air at low pressure can blow away dust and dirt without doing any damage. The outdoor coils can also be washed with a hose, but not with a high-pressure nozzle. It’s critical to keep the water flow gentle so you don’t crumple the fins that help to radiate the heat that needs to be released.

Stubborn or severe dirt on your coils is a problem for professionals to deal with. If you’re concerned about dirty coils or think you might need air conditioning repair in Calhoun, LA, don’t hesitate to reach out. 

Contact Mike Smith Heating & Air Conditioning, LLC. We provide “Professional grade service.”

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