Tuckers Air Conditioning, Heating & Plumbing Blog

How Dirty Coils Create AC Problems


Your air conditioning system has two sets of coils that are responsible for it to do its basic job of cooling your house. An AC works through a process called heat exchange, which is the movement of heat from one place to another. The job of the refrigerant coils in heat exchange is to directly interact with the air. The indoor coil (known as the evaporator coil) removes heat from the air blown over it, and the outdoor coil (known as the condenser coil) releases this heat into the air outdoors.

An AC’s coils can run into several problems that will require air conditioning repair in Rockville, MD to prevent the air conditioning system from turning inefficient, losing cooling power, overheating, or developing ice along the coils. The most common problem for the coils is when they get dirty.

How the coils work

The two sets of coils are made from copper or aluminum, metals that easily conduct heat. Refrigerant circulates through the air conditioning system to pass through both coils. When the refrigerant moves through the evaporator coil, it’s at a low temperature—around 40°F. As warm air contacts the coil’s surface, the refrigerant inside evaporates and absorbs heat from the air, cooling it. When the refrigerant moves through the condenser coil, it’s hot, and as the condenser fan draws air across the coil, the refrigerant condenses and releases its heat outdoors.

What happens when the coils become dirty

Dirt, dust, and other types of grime that can get onto the coils create an insulating layer. This makes it more difficult for the coils to exchange heat with the air around them. The indoor coil won’t be able to cool the air as effectively, and the outdoor coil will struggle to release its heat. This leads to several problems for the air conditioner:

  • The efficiency of the system will drop considerably as the air conditioner must work harder to do its basic job. It must run longer to reach the indoor target temperature because the dirty coils—either indoor or outdoor—limit its ability to carry out heat exchange.
  • The air conditioning system may overheat if the refrigerant won’t cool down enough because of dirty outdoor coils. This is one of the reasons an air conditioner might trip the circuit breaker. 
  • The indoor coil may freeze over because it can’t absorb enough heat to warm up the refrigerant inside it. The refrigerant will stay cold enough to freeze moisture on the coil’s surface. A frozen coil won’t be able to function and the AC will stop cooling. 

The good news is that dirty coils are an easy repair for our technicians to make. If you notice a plunge in your AC’s performance or efficiency, call us. We’ll check the coils—it’s one of the first things we investigate when trying to discover why an AC is underperforming. We can give the coils a complete cleaning without damaging them or any part of the air conditioner. 

At Tuckers Air Conditioning, Heating & Plumbing, we pledge to exceed expectations at every turn! Reach out to us for air conditioning repairs in Washington D.C., Montgomery, and Frederick Counties.