I have a new system that was installed just a few months ago. It’s an American Standard Freedom 95 Comfort-R forced hot air. Two stages of gas fired heat (highest is 60k BTU), one stage heat-pump / cooling 1.5 ton I think, 16 SEER.
Everything on this system works great except for a bit of an issue with the heat pump. When I purchased the system there was a claim that it could (efficiently) work all the way down to 25F. I thought this was ambitious but some of this modern stuff is pretty good. Well, turns out that it could not really do this. The system would stay on and would run indefinitely (using electricity) and only get up to maybe 60F or 65F when set to 70F.
OK, so the company came out and made some adjustments, checked for problems, refrigerant, and notably changed the crossover point to 35F. No-go, same result. They came out again and changed a few more settings (in the thermostat) but kept the 35F set point. Still mostly a problem, it worked great while they were here and the outside temp was 37F, but later that week it would sometimes work, sometimes not. Even one time I noticed it took 3 hours to get up to 67F when the outside temp was 48F, other days it might be faster or slower around the same temperatures.
They walked me through changing the set point to 40F, and this made things a little better, but still somewhat inconsistent. For reference, when on gas it can get the place up to 70F from 62F in less than 20 minutes. It’s a 1400 Sq. Ft. Condo in Boston. At my request, they did contact the manufacturer representative for an expert opinion but they said setting it to 40F was about all you could do, and they did not think it was any defect in the unit. They also said that even when within the temperature range needed, the unit can be affected by weather conditions like rain, sun, and wind. The condenser is located in a narrow alley outside my building, and right next to it is another condenser that I have for a Mitsubishi Mr. Slim 22 SEER heat pump that says it will work down to 15F and works great down to 5F!!!
My questions on this are, are these acceptable results? It only cost a little bit more to add the heat pump over the non-heat pump unit, and I had to pay some high electric bills during these trials, but with a set point of 40F the heat pump is only going to be working for a few months out of the year, and what about this inconsistent performance? Should I be expecting more? Could this unit be defective? Are there other units that COULD work down to 25F for a whole-house unit like this? American Standard only has one unit above this, with I think 19 SEER using a two-stage condense that is even larger than the gigantic one that I got. But it was a huge step up in price and would not have paid for itself anytime soon. I would like to hear from some other experts about this situation.
This leads me to another separate question I have about this. Does anyone know of some really powerful computer-controlled thermostats? The one that came with this system is pretty nice, but obviously it is not nice enough to detect that the heat pump isn’t cutting it and will keep running endlessly never reaching the temperature instead of switching fuels. I have seen there are some “Ethernet equipped” thermostats you can connect to your home network that provide a web management page, but looks like they otherwise have the same features as what I have.
I am talking about something REALLY computer controlled, like a piece of software. Something that would have more sensors and could detect which fuel to use based on actual output/consumption over time even being able to compensate in real time for weather or other conditions. Advanced energy management features that would get the most out of the multiple stages, variable speed fan, etc. I will bet there are some home automation products that might have this, but I thought I might ask if someone knows of anything that might be exactly what I am looking for.
Thanks very much in advance