Heatpump in heat mode with programable thermostat.

Was thinking of installing a programmable thermostat in our snowbird mobile home in FL but after finding out thermostats call for aux. heat (resistive) with a two degree change I'm leery, less I just use it when cooling and use override when heating and set and forget it. Just wondering what your opinions are. Thanks.
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On 12/28/2010 5:33 AM, Questor wrote:

Depends what you mean by "mobile home". If it is a standard trailer or motor home, they usually use a 12 volt DC control system. I really don't know about single and double wide, semi permanent 'mobile homes'. I've installed a Honeywell in my motor home because the nice fancy digital thermostat provided by the motor home builder, was simply crap. It suffered from major cycle-itis and there was no way to change it. In the motor home, I picked a thermostat that had internal relays to control the HVAC system. I also picked on that had a backup battery that also could be used for continuous operation in systems that have no 24VAC return wire at the thermostat. My system is actually 2 systems; a roof mounted AC/heat pump and a side mounted propane furnace. Each has it's own duct system. I had to add a miniature toggle switch to the Honeywell to provide a High/Low fan speed for the AC/heat pump. It seems to work well, except there are times I can't explain what it is doing. BTW, my heat pump also has an electric resistive heat strip that is switched in when the temp of one of the freon lines crosses some magic value. But in my case, it never worked as the sensor was never in contact with the freon line .... it is now but I'm not living in it full time. The whole thing is sort of a kludge. If you only want the furnace to run, you have to re-program the Honeywell to make that happen. I know how to do it, but I know my wife doesn't. If I ever sell the unit, I will put back the original thermostat. BTW, the Honeywell does provide very accurate control of the heat and AC.
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I wouldn't. You're right, heat pumps don't like cycling the temperature. Find a compromise temperature and let it go. We use gas fireplace logs to warm up the great room while we're sitting watching TV. The localized heat tends to cool off the master bedroom (the others are on the second floor so get warm), which I actually like. We have to keep the temperature in the house warmer than I like, anyway, because of the "forced cold air heat". It works out for the little heating we do here in Alabama.
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On 12/28/2010 11:27 AM, snipped-for-privacy@att.bizzzzzzzzzzzz wrote:

We have a heat pump with propane backup furnace. I don't particularly like getting up in the middle of the night to a cold house. So we set our programmable thermostat to 68 in the day. At 7PM it bumps up to a whopping 69. But, believe it or not, 1 degree makes you feel better, especially when you start winding down. Then, after midnight, we let it go to 67. This probably doesn't save up a whole lot, but it works for us. As far as cold air heating, this furnace has one of the variable speed blowers. We rarely feel the typical cold air draft of the heat pump I've heard of. Maybe I have to credit my HVAC guy that did the install in this new house, with doing a good job.
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Sure, I've found the same. When you're moving about you don't notice the cold as much. When sitting in front of the toob cold settles in fast. We now have propane logs in a fireplace in our great room. Works well, but the heat doesn't come on in the rest of the house (two heat pumps).
In our previous house (in Vermont, natural gas/hydronic) we'd set the thermostat for 59F night and then up to 65F about 6:00AM, then down to 62F after we went to work until 4:00, when it went to 65F again. If we felt cold, we'd bump the temperature. Now we keep it at 65-66F, and probably 67F in January/Februry when it gets cold.

I don't know how you avoid drafts with force air. The problem with heat pumps is that because of efficiency concerns the output air isn't high enough to take the chill off it. Moving cold air == draft.
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On 12/28/2010 5:33 PM, snipped-for-privacy@att.bizzzzzzzzzzzz wrote:

I think some of the improvement in this system comes from the variable speed blower. When there's little head, the speed seems to go down, which increases the register air temperature and produces less drafts.
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I think some of the better thermostats also let you decide when and if it calls for back-up heat, ie you can set the differential. Take a look at the Honeywell VisionPro installation manual. I'm not sure on this specific issue, but it has lots of parameters that can be changed. It also has adaptive recovery, which means you just set the temp and time you want it at that temp and the thermostat learns how much earlier to actually fire the system up to get it there.
Of course how much you can set the temp back with a heat pump system depends on the size of the system and climate.
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On 12/29/2010 9:08 AM, snipped-for-privacy@optonline.net wrote:

I do have a VisionPRO TH8000 thermostat. I really haven't changed any of parameters beyond what the HVAC guy did when he installed it. I also have the Honeywell HZ432 controller, which, besides being a zone controller, controls the entire system. The nice thing about this setup is that you can set the humidity in the summertime. If you don't have a whole house dehumidifier, it will use the AC to lower the humidity, which is what I do. Plus, having a 2 stage AC/Heat pump, it usually only runs stage one to dehumidify. Actually, I've only seen the AC go to stage 2 when you manually make a change. Even though the maximum summer temperature in this area last summer was about 96, here in the mountains where I am, the maximum was only 89, so the dual stage works well here. Also, the VisionPRO can apparently control a whole house humidifier, which I think I'll add for next year's heating season. Some of the manuals are a bit vague on this, so I'm not sure. I know the manual talks about programming to run the humidifier only on heat, or when the blower is on, or not at all, but I'm not really sure of how to hook it up. I'll need to do more research.
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