Today I performed a winter time maintenance on your furnace equipment. Overall everything is in fair condition. I started off checking the difference in temperature between supply and return air. I found a supply of 110° while return air was 70°F. Outside I checked the capacitor and contact and found them within manufacturer specifications. I took a close look at the coil, as it has been some time since we were out here to clean it, and found it very dirty. Customer purchased a chemical cleaning. I used NuBrite at a dilution of 6 parts water to 1 part NuBrite. This made a tremendous difference and should add some time onto your unit as well as drop your utility bill this summer. I finished up by treating the drain assembly with the leftover NuBrite diluted into a half gallon of water. This will kill any zooglea that has built up over the years. I do recommend having a duct cleaning done within the next 2 years. I noticed some microbial growth in one of the supply vents. Thank you for