At Reimer, we do everything in our power to ensure that your home comfort system works efficiently and effectively every time you turn it on. A home AC flush costs $75 to $250 to unclog the condensate drain line. Mold, mildew, dirt, and debris cause clogs in the drain line. If the drain line is not flushed regularly to prevent clogs, water collected in the drain pan overflows, causing water damage. You can use the AC’s circuit breaker to shut off the unit, but that should not be a permanent solution—circuit breakers are not designed to be used like light switches.