Central air conditioners cool houses and create a temperate haven to hide in when you're fleeing the pounding summer sun -- but the cooling nature of air conditioners can work against the machines if they aren't maintained properly. If blockages obstruct the air flow in and out of the system, the cool air can become trapped inside and lead to ice formation. Let untreated, a central air conditioner can become completely frozen over and stop blowing cool air. Defrosting a central air conditioner and removing dust or other obstructions helps restore the system to working order.
Turn off the air conditioner its control panel and at the circuit breaker. Leave the AC off until the air melts, which can take one to two days.
Turn on unit's fan without turning on the cooling system, although not all air conditioners feature this option. The air flow encourages the ice to melt faster.
Remove the units air filter and inspect it for cleanliness. Clogged air filters halt air flow and can freeze up units. Replace the air filter with a new one if necessary.
Move any curtains or objects blocking air conditioning vents.
Clean the unit's fan blades if you haven't done so in a while. Turn off the AC's power at the breaker, then run a vacuum over the blades to remove accumulated dust.
Inspect the condenser and evaporators coil while the power is switched off at the breaker. Wipe dust and debris from the surface of the coils with a soft-bristled nylon brush. Use a gentle touch to avoid damaging the coil fins as you clean.