I replaced my old analog thermostat with a new digital Honeywell RTH 3100C back in the Spring. Ever since, I noticed my heat pump is cycling on and off a lot more often. Finally discovered this Honeywell digital thermostat has a +or- one-degree differential whereas my old thermostat had a differential of at least 2 degrees if not 3 degrees. I checked with Honeywell Tehnical Support and the differnetial is fixed and can't be changed. My electric bills have increased significantly. Others tell me the frequent cycling on and off will cause higher electricity usage and consequently higher bills.

I have a Heat Pump with a single speed fan and auxiliary heat of a bank of electric coils. I would like to buy a Thermostat with a programmable differential that I can set for 2-3 degrees, compressor protection, efficient recovery where the aux heat won't come on if the heat pump itself can recover by itself. I have also read about thermostats that have programmable compressor cycle rates but I don't understand them

Can anyone recommend a Thermostat that would have these features and best fit my needs?

I wanty to do the same thing-replace our mercury-switch type one with a digital like we had in our other house-yes electricity etc is higher-but the temperature stability is better! We used to freeze because the temp would have to drop fairly low before the system would cycle on again.

What we've done is to buy a small electric fan-heater and use that at night in the lounge room-we get the heat while the rest of the house is not heated-we save a bucket-load of money on bills now! Central heating is a real energy waster.

If it is heating-just use a fan-heater, if it is aircon (cooling) u need then I suggest that your aircon be left as is.

Usually when you replace an analog thermostat with a digital one, two things happen. One, you are setting it at the same temperature as before, but the old stat didn't maintain that temperature... it allowed the house to get warmer. And two, unless your house has poor insulation, the more quick cycling usually won't increase your bill because the unit will run less each time it cycles. If your old stat kept swinging the temperature 2-3 degrees, try setting your thermostat 2-3 degrees higher. You probably won't notice the difference and your bill shouldn't change from the prior stat.

I have been told by people in the AC/Heating business that the short cycling on and off uses more electricity than a longer run time. They say it takes a compressor 5 minutes or so to get up to full efficiency. They say longer rune times and less cycles uses less electricity.

Check out the Total Line #450, this thermostat will do everything you asked for and more, good luck, Mike

Mmm interesting info for me as well-thanks everyone!