Sustainability
Dirty AC coils quietly raise your power bill
Why dust on evaporator and condenser coils cuts cooling and wastes electricity, what the US Department of Energy and Berkeley Lab say, and how to clean coils without a pressure washer.
In an Indian summer, the split AC is the hardest-working machine in the house. Most people clean the filter now and then. Very few think about the coil behind it.
What dust does to a coil
The US Department of Energy explains that an air conditioner's evaporator and condenser coils collect dirt over months and years of service. Dirt reduces airflow and insulates the coil, which reduces its ability to absorb heat [1]. The DOE also notes that replacing a dirty, clogged filter can cut an air conditioner's energy use by 5 to 15% [1].
Researchers at Lawrence Berkeley National Laboratory studied coil fouling directly and linked it to reduced airflow and lower system efficiency [2]. In short, a dirty coil makes the compressor run longer for the same comfort.
The pressure-wash problem
The usual fix is a yearly pressure wash. It takes a bucket, a plastic sheet, a lot of water and a technician's whole morning. Often the job is skipped, and the dust builds straight back up.
A foam that goes where a spray cannot
That is the job Aerosure AC Foam Cleaner was designed for. It is an expanding foam that wets the full depth of the fins, lifts dust and grease, and drains out with the condensate. No hose, no sheet, no mess.
- Switch off the AC, isolate power and open the access panel. Wear gloves and eye protection.
- Brush or vacuum off loose dust, along the fins.
- Shake the can and spray the foam evenly over the coil at the distance on the label. Keep it off electrical parts.
- Follow the label for rinse or no-rinse use. If you rinse, use gentle low-pressure water. Let it drain, refit the panel and restore power only when dry.
The full routine is in our 4-step AC coil foam cleaning SOP.
After cleaning, a protective coat such as Aerosure Coil Saver helps fins resist corrosion. See the full Aerosure range.
Quick answers
Does a dirty AC coil increase electricity use?
Yes. The US Department of Energy explains that dirt on coils reduces airflow and insulates the coil, cutting its ability to absorb heat. Berkeley Lab research also links coil fouling to lower efficiency.
How often should split AC coils be cleaned?
Check filters monthly in peak season and clean the indoor coil at least once or twice a year, more often in dusty areas. A foam coil cleaner makes this possible without a pressure washer.