Use area rugs that can be taken up and washed often. Have major appliances, such as furnaces, heat pumps and central air conditioners, inspected and cleaned regularly by a professional, especially before seasonal use. Change filters on heating and cooling systems according to manufacturer's directions. When first turning on the heating or air conditioning at the start of the season, consider leaving your home until it airs out. Have window or wall air-conditioning units cleaned and serviced regularly by a professional, especially before the cooling season.
Air conditioners can help reduce the entry of allergy-causing pollen.
But they may also become a source of biological pollutants if not properly maintained. Clean the coils and incline the drain pans according to manufacturer's instructions, so water cannot collect in pools. Have furnace-attached humidifiers cleaned and serviced regularly by a professional, especially before the heating season. Follow manufacturer's instructions when using any type of humidifier. Experts differ on the benefits of using humidifiers.