Mark saved the day for us. We had suffered for 2 1/2 days and nights with extremely high heat and a broken thermostat. We had called another repair person and he diagnosed the bad thermostat, but couldn't get the part for it. We called Mark and he promised he would do what he could for us to get us cooled down. (We are elderly and are affected by the heat because of medical issues.) He came with the new part and everything worked out fine. Very nice man, explaining all about the system and showing my husband what to look for in our heat pump system and how to care for it. Will recommend him to neighbors and friends. Thanks Mark and staff !