The 1983-built house we bought a year ago was our first experience with heat pumps. In this current cold spell our high end pump was not producing sufficient heat regularly and the “aux heat” in it would not come on. Nathan came out earlier this week, checked the whole system thoroughly as I watched and found it all was working well and wired correctly, including the aux heat and compressor. He explained that while the ********* thermostat was working correctly at the moment, it is possible that since it was old it might have intermittent failure. While he was here he also explained clearly to me how the heat pump cycles each hour, etc. An hour or so after he left, the fan would not work. I called and he returned shortly thereafter to see if a new thermostat actually would solve the problem. He installed and programmed it following my specific choices. It completely did and for the last few days all has been working perfectly. I was very pleased with his knowledge and repair skills but also his ability to explain the system at the right level of detail and in terms a customer can understand. Thanks again, Nathan!