I bought a 3.5 ton Trane xl 1200 heat pump in Sept. '05. When it heats up in the summer (over 105) the thing runs for 50 min. Out of every hour. When it tops 110, it runs nonstop and won't cool the house below 79 degrees (I have documented run times several times over the years). The 18 yr. Old Carrier it replaced never had a problem doing this. I only replaced it because it needed service and it was very old. I thought it would be better to put my money into a new, efficient unit. What a mistake. Trane techs have been coming out here repeatedly and tell me that this is normal operation. Really? I thought I'd save electricity by going from an ancient 8 SEER to a 12 SEER. Nope. Not likely when the unit is running all the time. Today they tried to tell me that my house isn't insulated well enough (didn't seem to bother the Carrier). My two next door neighbors (same houses, same insulation) went the cheap route and purchased Goodman units. They do not have these problems. I feel like an idiot for forking out an extra $2K for a (supposedly) top of the line unit which is obviously inferior to the cheapest unit on the market. On top of all that, the installation, by what is supposed to be the top rated Trane dealer in the area, was a complete botch job. The brought the wrong pitch rooftop stand, then they brought the wrong unit (left hand instead of right hand) and rigged my ductwork with flex ducts to make it blow in the right direction. I can't believe I paid top dollar for this. If they offered me my old battered Carrier unit back, I'd take it in a heartbeat.