If your air conditioner is iced over or obstructed by debris, turn it off and switch on the fan to defrost naturally. Clean or replace dirty filters to possibly restore functionality. Contact an HVAC technician to inspect for potential refrigerant leaks, which could be hazardous.

Air filters vary in rating based on material: fiberglass and washable types are MERV 3-4, blocking larger dust; pleated paper filters have finer pores, providing better filtration at MERV 5-8.

HVAC systems are designed to endure rain without damage, provided electrical parts are insulated and waterproofed, and rain can help clean accumulated dirt and dust from the outdoor unit.