We have a contract with Allied Services where they would come by twice a year to check our furnace and air conditioning. We haven't had any problems yet and am very satisfied with their services so far. Their workmen are always here and on time when you call; they don't try to make an excuse as to why they couldn't get here. They communicate well about any issues there are with our units and are very thorough with their work. Prices are reasonable; I mean, having the check-up twice a year can get a little expensive but not so much that they become out of line. Very happy with their services.