Super tune up performed today on a nine year old carrier heat pump with air handler. All electrical connections are tight with no corrosion. Biological growth is present inside of the air handler. Suggest adding a UV light to kill existing growth and prevent it from coming back in the future. 70/7.5 dual run capacitor was changed on this visit. Compressor and condenser fan motor are acceptable. Refrigerant levels are in range. Outdoor unit was washed and waxed. Suggest adding attic insulation to help with the efficiency of the home.