Carl's installed our furnace a number of years ago and we have had them come out to do yearly check-ups.Last year, they installed a new air conditioner. They are the best. They are always gracious, helpful, knowledgeable and on time. When they say they will be there, they will be. They do not overcharge and even offer their regular customers discounts on their yearly check-ups through mailing cards. $69 per check up.