As the air conditioner runs, dirt, leaves, cottonwood and other debris get pulled into the outdoor condensing unit. This clogs the cooling coil fins. Clogged fins restrict air flow needed to operate the air conditioner. As a result, the equipment loses it's cooling capacity. Electrical costs rise and equipment breaks down early. The average cost of a new A/C system is $3,500-$4,000 in a 2,000 square foot home. And the minimum cost to replace a burned out compressor is $1,000. According to EPA research 0.042" of dirt on an AC coil can reduce its efficiency by 21%.