My new apartment is all electric and has an 18k BTU heat pump (low-end Carrier split system, 14 SEER, newish), with 8k watts of backup resistive heat.
I like to sleep very cool and am gone for most of the day during the week. If I had a more conventional system like a gas furnace, I'd keep the apartment around 60F most of the time (that's also my ideal sleeping temperature), and program the thermostat to bump up to 70F when I'm home and awake (say, 5-10pm on weekdays and all day on weekends). Now, this runs exactly opposite the conventional wisdom of heat pump thermostat settings - keep them quite consistent around the clock.
For what it's worth, I'm not trying to be cheap, I just think it is an interesting question given the apartment can go most of the time with very little heat (it hasn't dropped below 66 yet this year inside, despite lows around freezing and days with highs in the 40s). That said, it gets pretty cold in Nebraska - think typical winter lows in the teens/20s and highs in the 30s with cold snaps colder than that.
Further complicating this, the apartment also faces south, so it seems to stay plenty warm even on cold days as long as the sun is out. I share most walls so the heat demand is quite low. I wouldn't be surprised if it never got much below 60F in here with the heat shut entirely off.
Any thoughts on the best option below?
A: have it programmed to 60F most of the time, and then use resistive backup heat (aux heat) to overcome the setback (the thermostat automatically jumps to aux heat if the delta is over one degree (which was smaller than I expected)). Due to that small delta, the aux heat will click on every time it comes out of setback. This is the "let the system handle it" approach, but the system's logic is limited to a cheap programmable thermostat which just automatically engages aux heat if the delta is over a degree or if it's taking too long to catch up.
B: keep it at 70 around the clock so that resistive backup (aux heat) is rarely needed, and rely only (mostly) on the heat pump.
C: keep it locked in EmHeat on the thermostat (locking out the heat pump entirely so it never runs) and program it to 60F night/away, and 70F when home.
My math suggests that aux heat comes out on top for costs if it runs 1/6 the time of the heat pump or so (given the heat pump likely pulls around 1200-1500 watts, and the heat strips are 8000 watts). That time split seems plausible, though, considering the air that the heat pump puts out is pretty lukewarm compared to the backup heat (think "is this even on?" vs. a steady stream of hot air - I'd guess 80 or 85F vs. 125F, based on a quick Google).
If I had a gas furnace and the heat pump, I think the furnace would be the clear winner here, but it's nice not having a gas bill and the associated fees for just an apartment (fees that would probably eclipse usage). My electric rate is 9 cents per kWh, for what that's worth.
I like to sleep very cool and am gone for most of the day during the week. If I had a more conventional system like a gas furnace, I'd keep the apartment around 60F most of the time (that's also my ideal sleeping temperature), and program the thermostat to bump up to 70F when I'm home and awake (say, 5-10pm on weekdays and all day on weekends). Now, this runs exactly opposite the conventional wisdom of heat pump thermostat settings - keep them quite consistent around the clock.
For what it's worth, I'm not trying to be cheap, I just think it is an interesting question given the apartment can go most of the time with very little heat (it hasn't dropped below 66 yet this year inside, despite lows around freezing and days with highs in the 40s). That said, it gets pretty cold in Nebraska - think typical winter lows in the teens/20s and highs in the 30s with cold snaps colder than that.
Further complicating this, the apartment also faces south, so it seems to stay plenty warm even on cold days as long as the sun is out. I share most walls so the heat demand is quite low. I wouldn't be surprised if it never got much below 60F in here with the heat shut entirely off.
Any thoughts on the best option below?
A: have it programmed to 60F most of the time, and then use resistive backup heat (aux heat) to overcome the setback (the thermostat automatically jumps to aux heat if the delta is over one degree (which was smaller than I expected)). Due to that small delta, the aux heat will click on every time it comes out of setback. This is the "let the system handle it" approach, but the system's logic is limited to a cheap programmable thermostat which just automatically engages aux heat if the delta is over a degree or if it's taking too long to catch up.
B: keep it at 70 around the clock so that resistive backup (aux heat) is rarely needed, and rely only (mostly) on the heat pump.
C: keep it locked in EmHeat on the thermostat (locking out the heat pump entirely so it never runs) and program it to 60F night/away, and 70F when home.
My math suggests that aux heat comes out on top for costs if it runs 1/6 the time of the heat pump or so (given the heat pump likely pulls around 1200-1500 watts, and the heat strips are 8000 watts). That time split seems plausible, though, considering the air that the heat pump puts out is pretty lukewarm compared to the backup heat (think "is this even on?" vs. a steady stream of hot air - I'd guess 80 or 85F vs. 125F, based on a quick Google).
If I had a gas furnace and the heat pump, I think the furnace would be the clear winner here, but it's nice not having a gas bill and the associated fees for just an apartment (fees that would probably eclipse usage). My electric rate is 9 cents per kWh, for what that's worth.
