What Causes My Central Air to Ice Up?

Sometimes ice and frost can build up on a central air conditioning unit. When this occurs, the air conditioning inside the house can seem to fail, pumping out air that isn't as cool as you'd like.

Air Flow Problems

Sometimes frost builds up on a central air conditioning unit.

If air does not flow freely through the air conditioner's coil, the unit can freeze up. Dirty air filters, obstructed air ducts or a dirty evaporator coil can impede air flow. When this happens, the moisture that the air conditioner has pulled from the air can form frost, rather than draining away as it should.

Lack of Refrigerant

If your central air conditioner doesn't have enough of a refrigerant charge, it can freeze up. Recharging refrigerant is a task that must be done by a qualified repairman certified by the Environmental Protection Agency. Icing can also occur if the metering device fails to provide enough refrigerant to the evaporator coil.

Hose Leaks

Certified repairman are also required to fix any hose leaks, which can be a cause of air conditioner icing. Ice will form at the site of leaks and continue to grow as the air conditioner is used.