Heating/Cooling Utility Bills

[BirdieBelle]

Originally Posted by CountryGirl2b=

You might want to repost this in the HOUSE section - might be some HVAC type people over there?

https://www.city-data.com/forum/house/

I was thinking this, but the only problem with posting it in that forum is that you have folks from all over the country who don't understand what our humidity is like and who will nitpick down to the most technical aspects of HVAC use.

I'm just saying, OP, you may get way more than you bargain for in the House forum.

[Rutt Roh]

Originally Posted by DubbleT

Kind of. Basically you are trying to keep from using the AUX heat, which will kick in when you try to heat the house too fast.
When I come home from work I kick mine up by about two degrees, let it reach the higher temp (takes less than thirty minutes usually) and then kick it up another two degrees if I'm still not comfortable. Drop it back down at bedtime.
As long as you warm the house up in small increments like that you should not see the AUX heat come on, unless outside temps drop into single digits, and then all bets are off.

Good to know. I think I'll have to up the temp a little at a time - about 2 degree increments as you mentioned.

Now as far as everyone's homeowner experiences in Nashville with heating costs on a utility bill for an all electric home (with a heat pump), would it be more expensive overall to:

1. Set the temp at 63-65 when gone for more than 5 hours or out of town, then kick up to 67-68 as needed when you get back to prevent the AUX from going on (only increasing by 2 degree increments).

2. Set the temp to 60 when gone for more than 5 hours or out of town, then kicking it up to 67-68 as needed when you get back. I know that will set the AUX to go on for a little bit due to the larger temp range, but I'm not sure if it'd be more cost effective this way because it'd be easier to maintain a lower temp without the heat kicking on all the time to maintain that 'higher' temp as in option 1 while you're out of town.

I know the rule of thumb is that you save roughly 1% on your monthly electric/heating bill if you knock the temp down by 1 degree.

Sorry if this all sounds silly, but I do appreciate your inputs!!

[groovamos]

From a purely cost-of-energy basis, when you are not home, the temperature would be at the lowest you could go without jeopardizing the plumbing in freezing weather. Same reasoning goes for when you are under covers at night. Anyone with education in the hard sciences, engineering or mathematics could show you why this is the most energy thrifty, by drawing you a plot of outside temperature, superimposed on the plot of inside temp, vs. time. The cost of heating your home is actually the cost of heating the environment of your home with the heat escaping the home. This heat loss per hour is proportional to the difference in the inside and outside temperatures. The total thermal energy loss for a given time period is proportional to the shaded area between the two plots over the time period. So naturally the area will be smaller if the plot of inside temp sags downward as much as practical while you are gone, towards the outside temp. In engineering terms, the time integral of the temperature differential is to be minimised for economical energy usage.