A year and 3 months ago, we had crack in our heat exchanger, and so we had it replaced by Allied Services. In July, we had a heat pump put in. After that, our thermostat read out went blank. We called the serviceman, and he thought there was something wrong with the thermostat. For awhile it seemed to be okay, then kept blacking out. We called again, they checked it out, and they said our furnace overheats and we have to get a new one. The heat exchanger cost $1,500, and I don't know why they didn't know about it overheating then. I hoped we would get a discount on the heat exchanger, but they said they would not cover that. To replace everything it will cost us over $4,000. The serviceman was nice, good, and explained everything thoroughly, but my main complaint was that they should check more thoroughly.