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hello,
i have a 3k SFH and a newer programmable thermostat....
i used to make the temp 70 during the house we're home and 64 or 65 during the night and then 68 or 69 when we wake up in the morning...
what i found is that if the system is trying to heat up the house to more than 2 degrees (ie. going from 64 to 69 is +5 degrees).....if this difference is any more than 1 or 2 degrees, then the emergency (Aux) heat comes on...and that will use CONSIDERABLY more energy.
This Aux head is used until the desired temp is reached.
now, my question is this: is it worth it to lower the desired temp to 64 or 65 during the 'off hours' and suffer the additional cost/energy consumption of the Aux head usage OR, is it better to just have a constant (or near constant) temp set during on/off hours? (ie. between 68 and 70 at any given times)
I'm no expert but I think it's better to keep the temps lower at night but not more than a few degrees if the aux heat is coming on. In our house, the aux heat runs on electricity and the regular on gas and the electricity to run aux heat costs more. In the summer with the a/c that probably isn't an issue for you so you can set the temps at a wider range. But with the heat you may be better off keeping the temps closer to the same.
now, my question is this: is it worth it to lower the desired temp to 64 or 65 during the 'off hours' and suffer the additional cost/energy consumption of the Aux head usage OR, is it better to just have a constant (or near constant) temp set during on/off hours? (ie. between 68 and 70 at any given times)
You'd have to crank the numbers. Start out by finding out the BTU for each heating method, normal and aux. For example, our normal is a heat pump and our aux is natural gas. You can calculate the BTU for each and calculate the cost by the utilities' (electric and gas) use.
Figure out how long it takes each to raise the temperature.
If the non-use or low temp time is long enough, then it is cheaper to keep it low or OFF.
Is it a heat pump? If so, you need a programmable thermostat spcifically designed for heat pumps because they're designed to bring temperatures up more slowly so that the emergency heat doesn't cycle on. (and even if it's a different system, that kind of programmable might help if you're trying to avoid the emergency heat kicking in)
Is it a heat pump? If so, you need a programmable thermostat spcifically designed for heat pumps because they're designed to bring temperatures up more slowly so that the emergency heat doesn't cycle on. (and even if it's a different system, that kind of programmable might help if you're trying to avoid the emergency heat kicking in)
Yes, i have a heat pump.
i do have a very new, (also somewhat expensive model) programmable therm. i'm not sure if it's specifically 'designed for heat pumps' as you suggested. how would one check? what's the difference with "other" kinds if any?
Also, another thing to mention.....Sometimes, there is only 1 degree difference between where the temp is and where it's trying to go and the aux comes on!!!!!! sometimes there is NO degree difference (ie. going from 69 to 69 to maintain the temp i guess) and the therm shows "Aux Heat ON".
The thermostat box should specifically state that a particular model is suitable for use with a heat pump. From what I remember at Lowe's, they'd have about 10 programmable thermostat options, but only two would be labeled for heat pump use.
The thermostat box should specifically state that a particular model is suitable for use with a heat pump. From what I remember at Lowe's, they'd have about 10 programmable thermostat options, but only two would be labeled for heat pump use.
Our Honewell 7500 has instructions for wiring specifically for heat pumps. You might double check that the connections are correct. It might be that something isn't hooked up right.
So, here's what i've learned so far....from talking to the manufacturer....
These are things i didn't know before so maybe it will help explain this stuff to someone else as well...
Emergency Heat: when your heatpump doesn't work and you're running on the electric coils alone...VERY expensive since you're using a lot more energy...
Aux Heat: when your Heat Pump and the electric heater are working at the same time. Also expensive. less expensive than the Emergency heat
Heat: when your heat pump works alone. the most sensible/cheapest option. this is what it 'should' be on whenever possible....
IF you have a sensor outside: the Aux heat comes on if the outside temp drops to a set temp. (ie. it'll only come on if the temp outside drops below....30F let's say
IF you don't have a sensor outside: The Aux comes on based on the heat pump usage. ie. if the heat pump is used...this much..., then aux comes on to help.
i personally don't have a sensor outside.....i'm currently trying to figure out how to modify that heat pump usage rate....if at all possible...
Aux Heat: when your Heat Pump and the electric heater are working at the same time. Also expensive. less expensive than the Emergency heat
Is this (always) true? I didn't know that. However, my system is heat pump with a natural gas furnace as the AUX and Emergency heat.
It's been pretty chilly here in Huntsville the past couple nights. I'll force it into AUX heat by setting the temp to three or more degrees above the room temp and see if the heat pump is ON too.
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