System is 20 years old utilizes are 22 refrigerant that is no longer manufactured. Last service call by others added by almost 5 pounds of refrigerant. This is not normal as there is a leak somewhere. You can no longer get parts for our 22 refrigerant. Recommend that system shouldbe replaced. As of right now, the air conditioner is working. Ballpark to replace the coil and outdoor condenser is about $7500. nothing‘s wrong with the furnace, so it will stay however controls have to be added to it to accommodate the new refrigerant. Ductwork is in good condition. Combustion 23 ppm carbon monoxide 4.2 CO2 13% oxygen system is burning fine. Furnace looks like it’s in great shape.