Regulating heat sources

[bowhunterjac]

Not sure this is the proper forum to ask this... We recently moved to a smaller "retirement" home which was originally a bungalow along a major river. The prior owner had a large woodburner on the first floor and a smaller one in the basement, both heated the majority of the house. The first floor is mostly one big room with a lot of windows looking over the river, mostly exposed basement and 2 bedrooms and a bath on second floor. We didn't feel like dealing with wood so we sold the wood burners and bought 2 free standing propane stoves, one for the main floor and one for the basement. We had an electric heat pump put in with our central air when we had it replaced. The heatpump has ducts on the main floor and the second floor. The second floor bedrooms and bath have electric baseboards, and the main floor has a few electric baseboards as well. The basement has no heat other than the gas stove we put in.

I'm looking for advice on how to regulate all these heat sources to be the most energy efficient.

We use the propane stove in the basement on a thermostat set at about 58 to keep it decent down there.

When the temp is in the 30's and above we use the heat pump and (when we're home) the propane stove on a thermostat set at 71, on the main floor.
When it gets into the 20's or lower we use the baseboards and the propane stove (when we're home) on the main floor.
I'm not sure if it's more efficient to use the heat pump when the temp is below the 30's and it seems to be running hard. Or is it more efficient to run the elect baseboards when it's below the 30's.

To save propane we basically use the main floor propane stove to keep it nice and warm only while we're home.

 

[Bret Chase]

unless you want to get into facilities - level programmable controls with a delta-t sensor... you're gonna have to do it manually... set the thermostat of heat sources you want to use primarily at a higher temp, and the ones you don't at a lower temp... don't want to use the stove when youre gone... turn it off. the secondary sources will only kick on if your primary cant keep up.

it also depends on how we are defining efficiency $ to btu, total energy use, $ to comfort, total energy use to $, btu-input to btu output, etc

not sure about in your area, but here... burning propane is still quite a bit cheaper than electric resistance heating.

 

[danimal1968]

You might try posting this (or asking a moderator to move it) to the Green Room. There seems to be more discussion along these lines there.

But on heat pump vs. electric resistance, it depends on the design of your heat pump. More modern heat pumps can maintain their efficiency and effectiveness below 30 degrees, but that really depends upon the model you had installed, and how its efficiency drops as the temperature drops. In general, there is a point at which resistance heating will be more efficient than the heat pump, but where that point is depends upon the design of the heat pump.

 

[bowhunterjac]

Thanks for your replies...!! I moved a copy of this to the green room too. The heat pump keeps the place nice until it gets down into the 20's, then it just doesn't keep up. Then we were turning it off and going to the baseboards. I just can't help but to think we're killing the elect bill when running the baseboards compared to the HE heat pump. I was thinking that cost to coast I was spending more for LP than elect. But it's possible that's not so. LP is $2.99 a gallon right now, just had the tanks filled. Not sure how that might compare to elect BTU for heating output....

 

[Bret Chase]

Propane has 91,000btu per gallon. there are 3.41 btu per watt, therefore a gallon has 26.7kw of energy in it. 2.99/26.7= $0.11/kw

Therefore... btu per btu... (and ignoring heating unit efficiencies)

$2.99/gal propane costs the same as $0.11/kwH electricity.

I pay a LOT more than $0.11/kwH for electricity.