How Often Should You Clean Your AC Coils?

Published 4/22/2025

Homeowners should get their AC coils cleaned at least once a year. If you live in an area with high levels of dust, more frequent cleaning (3-6 months) is recommended. Clean AC coils promote efficiency, reduce energy use, and extend the lifespan of your AC system.

Take Chicagoland's muggy summers, for example. When homeowners skip regular AC maintenance, the coils inside the unit can get coated with dust, pollen, and humidity residue. This gunk can knock down your cooling power and increase your electricity bill. In this article, we'll review the importance of cleaning your AC coils, the different types, and when it's best to schedule air conditioner cleaning services from reputable HVAC companies like Mr. Duct.

When Should You Clean Your AC Coils?

The best time to clean your AC coils is in spring, before the start of the cooling season. Scheduling air conditioner cleaning services from companies like Mr. Duct will put homeowners in the best position for the times they need the AC running smoothly the most, like hot summer days.

There are a few signs that can indicate that your AC coils need cleaning. The first is weak airflow or if certain rooms are not reaching the set temperature. If the AC system is running longer than normal, this may also signal dirty coils. And, one of the most tell-tale signs of dirty AC coils is a musty or dirty odor from your vents. All of these should prompt you to seek air conditioner cleaning services from a reputable HVAC company like Mr. Duct.

The Importance of Cleaning AC Coils

Neglecting the cleaning of your AC coils can have a significant impact on your system's efficiency, lifespan, and indoor comfort. Dirt on the coil surfaces prevents efficient heat transfer because it acts as insulation. Layers of dust and debris can also force your air conditioner to run longer and consume more electricity. Some studies have even shown that dirty evaporators or condenser coils can increase an AC system's energy usage by over 30%. This underscores the importance of having your AC coils professionally cleaned by Mr. Duct before the summer arrives.

Types of AC Coils

In standard central air conditioning systems, there are two types of AC coils that perform complementary functions: the evaporator coil and the condenser coil. Both of these components are heat exchangers made of metal tubing with many thin fins to increase surface area.

The evaporator coil is typically located within the air handler or furnace plenum and is responsible for absorbing heat from the indoor air. The process involves cold liquid refrigerant flowing into the evaporator coil, turning that refrigerant into a gas through evaporation, pulling the heat out of the air, and removing moisture. This component relies on the HVAC system's air filter to keep dust from accumulating on the wet fins.

The condenser coil resides in the outdoor unit, and its job is to move the heat absorbed from inside your home to the outside air. After the refrigerant absorbs heat indoors, it travels to the condenser coil as a hot, high-pressure gas. As this gas flows through the coil's tubing, the outdoor fan blows air across it, helping the refrigerant cool down and condense back into a high-pressure liquid, which releases heat in the process.

Evaporator Coils vs. Condenser Coils

There are several key differences between evaporator coils and condenser coils, both in function and how each type can get dirty. Fundamentally, the evaporator runs cold, and the condenser runs hot. Evaporator coils are usually located indoors, while condenser coils are located outdoors in the exterior AC unit.

Because of their locations, the coils encounter different types of contaminants. The evaporator coil only interacts with the air that's circulated through your HVAC vents. This air is filtered by your AC system's air filter before reaching the evaporator coil. Over time, dust will bypass the filter through small gaps and create a sticky gray film over the fins.

For condenser coils, exposure to the outdoor air can cause issues. Dust, dirt, pollen, and debris from the environment can get pulled through the condenser fins. A classic example of this in Chicagoland is the cottonwood tree fluff. This can easily blanket the outdoor coil in a matter of days during late spring.

In both scenarios, scheduling air conditioner cleaning services from Mr. Duct will get rid of all of the dirty elements from your AC coils. Keeping up with regular air conditioner cleaning services also helps reduce strain on your system and prevent costly breakdowns.

Schedule Air Conditioning Cleaning Services with Mr. Duct

With over 20 years’ experience in residential air conditioner cleaning services, and hundreds of testimonials and reviews, Mr. Duct not only assists homeowners with AC maintenance, but also offers AC installation and repairs. What sets our HVAC company apart is our upfront and honest pricing, highly-certified technicians, and white-glove customer service. Contact Mr. Duct today to schedule air conditioner cleaning services for your home or business. And take advantage of our money-saving air conditioner cleaning services coupon or air conditioner replacement services coupon when you schedule your appointment.