Heat transfer is the whole job of a coil. Air passes across thin metal fins, gives up its heat to the refrigerant inside, and comes out cold. Put a layer of dust, grease or salt residue on those fins and you have insulated the exact surface that was supposed to be transferring heat. The system runs longer to reach the same temperature, and longer runtime is the energy bill.

On a big commercial system that penalty scales up fast. A rooftop unit serving a restaurant dining room might run twelve or fourteen hours a day in July. Every point of efficiency you lose to a fouled condenser coil gets multiplied by all those hours, across every unit on the building.

Cleaning covers more than the coil. Blower wheels load up and lose capacity, drain pans grow biofilm, and duct interiors collect whatever the filters missed. We clean the parts that actually change how the system performs, and we tell you which ones on your building were the real problem.

Salt is the big one near the water. Salt-laden air carries onto condenser coils and combines with dust into a crust that both insulates the fins and corrodes them. Buildings in Miramar Beach, Grayton Beach and Panama City Beach get this year round, and a rooftop unit takes it with no shelter at all.

Grease is the other one, and it comes from kitchens. Vaporized cooking oil that gets past a hood filter migrates and settles, and once it is on a coil or a blower wheel it holds every particle of dust that touches it. Restaurant equipment fouls far faster than office equipment for exactly this reason.

Then there is our humidity. Because the coil stays wet nearly continuously through the long cooling season, anything that lands on it sticks and stays damp. That is a growing environment, which is where the musty smell in the first minute of operation comes from, and why drain pans and lines need attention on the same visit.