Dirty condenser coils increase power costs. When the coil becomes fouled with dirt and grime, it cannot provide adequate or designed heat transfer. The debris insulating effect causes higher discharge pressure. The higher discharge pressure increases amp draw and run of the compressor, at the same time reducing capacity. Equipment operating with dirty coils may use as much as 37% more energy than equipment with clean coils. Let's take a look at a 10-ton air conditioning system with a typical kilowatt cost operating for an average cooling season of 1,500 hrs. It costs approximately SR. 4,992 with clean coils. However, when the condenser coil becomes dirty, the six month cost of operation escalates 37% to SR. 6,839. With rising energy costs, like those experienced here in Saudi Arabia, the cost of a dirty coil can be even greater. From this example, just by keeping coils clean, SR. 1,847 savings can be realized in one cooling season. That's savings of SR. 184.7 per ton. Areas with longer cooling seasons or higher than average power costs can realize even greater savings. The cost of dirty coils goes even further. As dirt grime collect on the condenser, they restrict heat transfer, causing the compressor to work harder, more heat is added to the system, thus causing the head pressure to rise. Rising head pressure will result in a loss of cooling capacity of up to 30%. If our 10-ton system with a 30% loss now only provides 7 tons of cooling, the system not only will cost more to operate, it will provide less cooling. This loss of capacity will typically be most noticeable on the hottest days, when cooling is needed most.