Best energy option....

[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.

 

[woodgeek]

whats your price for propane and electricity?

 

[bowhunterjac]

I know my propane is $2.99 / gal I'd have to look at the electric bill to check

 

[bowhunterjac]

I know my propane is $2.99 / gal I'd have to look at the electric bill to check

Looks like elect is 6.991 cents per kWh

 

[woodgeek]

The 6.99 cents/kWh sounds like the generation charge....try taking the whole monthly bill amount and dividing it by your monthly kWh used to get an 'all in' figure....

 

[peirhead]

Good insulation in the house??...newer heat pumps should be good down to about -15F (-20C)...just make sure you keep the snow cleared away from them so they can breathe. Your electric rate looks pretty cheap....we pay close to 15 cents per KWh plus $25/month service charge.

 

[jebatty]

Bowunterjac, my wife and I pretty much did the opposite of you. In 1990 we bought a lake cabin, now upgraded to our full time home. Cabin was heated with electric baseboard. Left that in place but added a woodstove in the living room. The stove ever since is the primary heat source. My wife loves to stove, the warmth, and no heating bills too, plus loves the guy (me) who cuts, splits and stacks it, and then who fills the big woodbox in the living room (about 3-7 days supply, depending on outside temperature). And I love the person (her) who vacuums once in awhile the 12 foot "path" from the woodbox to the stove.

 

[iamlucky13]

The 6.99 cents/kWh sounds like the generation charge....try taking the whole monthly bill amount and dividing it by your monthly kWh used to get an 'all in' figure....

The base charge doesn't matter. He pays that whether he uses the heat pump and baseboard heat entirely, or uses propane entirely. The only exception is if he was considering going off grid, but that won't be cheaper.

So the comparison really is at the $0.0699/kWh.

Good insulation in the house??...newer heat pumps should be good down to about -15F (-20C)...just make sure you keep the snow cleared away from them so they can breathe.

If it's a 2 stage heat pump and sized to keep up with the heat loss all the way down to that temperature. Most academic discussions I've seen consider sizing a system to -15F either putting a heat pump in an inappropriate climate, or oversizing it relative the typical conditions. Oversizing can hurt your overall efficiency worse than occasionally needing auxiliary heat.

With 2 other heat sources, I'd expect most installers to suggest a small single stage unit to keep their bid low.

 

[bowhunterjac]

The 6.99 cents/kWh sounds like the generation charge....try taking the whole monthly bill amount and dividing it by your monthly kWh used to get an 'all in' figure....

Looks like .14 kWh if I figured it right... We're on a budget so I'm not 100% I'm looking at the correct monthly bill....

 

[bowhunterjac]

Bowunterjac, my wife and I pretty much did the opposite of you. In 1990 we bought a lake cabin, now upgraded to our full time home. Cabin was heated with electric baseboard. Left that in place but added a woodstove in the living room. The stove ever since is the primary heat source. My wife loves to stove, the warmth, and no heating bills too, plus loves the guy (me) who cuts, splits and stacks it, and then who fills the big woodbox in the living room (about 3-7 days supply, depending on outside temperature). And I love the person (her) who vacuums once in awhile the 12 foot "path" from the woodbox to the stove.

I really wanted to keep the big wood burner, it was a nice model and would have heated us out of hte place. But my wife grew up with heating her house with one and hated the smell and work of having one.... Happy wife, happy life.... Gotta admit the propane is clean and easy...

 

[bowhunterjac]

I guess I'm not looking for the totally perfect answer... Mostly is it more efficient to try and run the heat pump when it's really cold and it's more than likely using the auxiliary heating unit on it, or turning the heat pump off and going with the elect baseboard heat when the temp really drops. I'm not sure the propane stove would adequately heat the first floor on it's own so we use it to make the place toasty in the evenings when we're home.

 

[iamlucky13]

I'll step back a bit to clarify, the figure to use is any charge based on how much you use. So if there are multiple base charges for low, medium, and high volume users, we can recalculate with those factored in.

For 6.991 cents/kWh and $2.99/gallon:

- Electric baseboard heat: $20.47/million BTU
- Heat pump (using the performance specs for my single stage, ducted unit): $9.18/million BTU
- Propane stove (assuming 85% efficiency): $38.66/million BTU

So my advice is to use the heat pump as long as it's not running almost constantly. Some would advocate using it until it's running constantly, but I'm reluctant to rack up too many nonstop hours. Also the efficiency of the heat pump declines with the temperature. My rough calculation above is based on a mild climate seasonal average. When you get down to 30 degrees, it's probably more like $12-15/million BTU.

Use the baseboard heat when it gets colder outside. Use the propane sparingly to make things more cozy or if it gets really cold and your other heaters aren't keeping up.

It's also more difficult to make a call with auxiliary heat factored in. A heat pump running with auxiliary heat kicking on should still be less expensive than the baseboard heat, but not by much, so I wouldn't fret about making the wrong choice when it gets really cold.

 

[bowhunterjac]

It's also more difficult to make a call with auxiliary heat factored in. A heat pump running with auxiliary heat kicking on should still be less expensive than the baseboard heat, but not by much, so I wouldn't fret about making the wrong choice when it gets really cold.[/quote]

Sounds like we were on the right track then.... Guess I needed a little reassurance that we were making a decent choice. I just hate the thought that I may have been missing the boat and racking up a bigger bill than necessary with using the wrong source at the wrong time.... THANKS...!!

 

[jebatty]

.... Happy wife, happy life....

Couldn't agree more. Logic based on hard numbers does not outweigh logic based on aesthetics, preferences and a happy household. Not that it would make any difference at this point in time, but since you did have a wood stove, I assume you have a Class A chimney in place. Based on the following info, and the fact that you are on a budget, your wife just might consider limited use of a smaller, classier wood stove for ambiance and also during the really cold periods when cost of the heat pump, baseboard or propane made budgetary sense. My calculation of your costs:

Electricity: baseboard btu/kw = 3412; heat pump COP of 3 = 10236; COP of 2 = 6824
Electricity kwh per MMbtu: baseboard = 293; heat pump COP of 3 = 98; COP of 2 = 147
Electricity cost per MMbtu @ $0.0699/kwh: baseboard = $20.48; heat pump COP of 3 = $6.85; COP of 2 = $10.27
Propane btu/gal = 91,500
cost per MMbtu @ $2.99/gal and 85% efficiency: $38.44
Wood cost per MMbtu, cut/split/delivered @ $200/cord (assume average 21 MMbtu/cord) and 70% efficiency: $13.60

As temperature drops, your heat pump COP drops, and at some point you will be using electric resistance heat with the heat pump, same electric cost as baseboard. But at your energy costs, it appears that electricity will always be less expensive than propane.

I too question the $0.0699 for electricity kwh cost. Where I live there are 3 cost factors per kwh charge, and all three must be added to get the actual kwh cost: generation cost ($0.04), wholesale power cost adjustment ($0.04) and distribution cost ($0.03) = total cost $0.11/kwh. And then the base charge of $14.00 is added. The base charge cannot be avoided.

 

[Circus]

Best energy option is a market question that changes all the time. Sounds like you can already change fuels sources at will. Last year propane was almost $5, today it's about $1. Heat accordingly.

 

[peakbagger]

Generally conservation if your best way to save money no matter what you heat with. A poorly installed ducted heat pump system can lose half the heating or cooling in the ducts if they aren't sealed well and outside of the conditioned space. Attic duct runs are somewhat infamous for being particularly inefficient. Standard central HVAC also tends to heat or cool the house to one temperature and most people don't need the entire house to be that way. Standard fixed speed heat pumps switch to resistance heat at some point around 35 degrees, anything lower and you are heating with electric heat with the duct loss added in. Mini Splits are heat pumps and some have vatriable speed compressors that run down to -15 deg F albeit at a reduced output. Since you have propane backup they would be nice fit and compared to conventional ducted heat pump the costs savings could be significant.

If you have had an energy audit and the house is tight, dependent on your utility and sun exposure consider putting in solar panels to offset power use. Panels combined with minisplits with net metering can lead to free heat. My break even point is around 20 deg F and since I net meter, I can run most of the winter "for free". There is a capital cost to recover but once you have paid it, the cost is mostly free.

 

[begreen]

If it's a 2 stage heat pump and sized to keep up with the heat loss all the way down to that temperature. Most academic discussions I've seen consider sizing a system to -15F either putting a heat pump in an inappropriate climate, or oversizing it relative the typical conditions. Oversizing can hurt your overall efficiency worse than occasionally needing auxiliary heat.

With 2 other heat sources, I'd expect most installers to suggest a small single stage unit to keep their bid low.

That's correct. I went for the higher bid to get an efficient 2 stage unit. It's coupled with a variable speed air handler. The duct work is well sealed and insulated. This setup has performed well in our climate for the past 9 yrs. and has been quite cost effective. We burn wood when it's colder instead of letting the strip heaters do the cold weather hauling.

It pays to get several quotes. There was a $13,000 difference between our 5 quotes. The lowest was a single-stage system in spite of our asking for a 2 stage quote. The highest was a Home Depot sponsored contractor. They had the slickest presentation and the newest truck . It was for a nice Trane system, but their bid was $11K over what we paid for our American Standard setup and equal to a quote we had received earlier for a geothermal system.

 

[woodgeek]

FYI, in PA there is a generation charge, a distribution charge and a service charge.

Y'all are assuming the marginal cost is 6.99 cents, and that the difference is a monthly fee indep of usage. My guess is that his marginal cost is closer to 15 cents/kWh. Factor that into the analysis.

 

[iamlucky13]

FYI, in PA there is a generation charge, a distribution charge and a service charge.

Y'all are assuming the marginal cost is 6.99 cents, and that the difference is a monthly fee indep of usage. My guess is that his marginal cost is closer to 15 cents/kWh. Factor that into the analysis.

That occurred to me. If bowhunterjac would like to double check his bill to make sure the correct incremental charges are used, I can recalculate my figures pretty easily.

 

[Highbeam]

FYI, in PA there is a generation charge, a distribution charge and a service charge.

Y'all are assuming the marginal cost is 6.99 cents, and that the difference is a monthly fee indep of usage. My guess is that his marginal cost is closer to 15 cents/kWh. Factor that into the analysis.

You're almost certainly right. The 7 cents is the teaser rate that the power company puts on your bill. The proper method for this estimate is to just divide the bill by the consumption. True flat base fees are usually a trivial 6$ or some other low number to again give the impression that your power company is the nice guy.

 

[maple1]

You're almost certainly right. The 7 cents is the teaser rate that the power company puts on your bill. The proper method for this estimate is to just divide the bill by the consumption. True flat base fees are usually a trivial 6$ or some other low number to again give the impression that your power company is the nice guy.

Agreed.

I think if you take your monthly bill and divide by kWh, for a whole year, and see what the difference is between high & low use months, there won't be a big $/kWh difference and it will be a lot more than 0.07/kWh. My low is 0.17, high is 0.18, all in.

 

[STIHLY DAN]

I agree with the rest of them, electric rate has to be higher. Also are these vent less gas stoves? If so that's 100% efficient, but beware these can be carbon monoxide monsters. Just a smidge out of adjustment and there can be issues.
They do make inverter driven ducted heat pumps as well. Mini splits are not the only ones anymore.

 

[begreen]

Yes, I would have put in a ducted inverter system if they had gained traction here. When we got our system installed in 2006 only Sanyo sold them in the northwest and no one had installed one. Now there are options from many companies.

 

[Dune]

The base charge doesn't matter. He pays that whether he uses the heat pump and baseboard heat entirely, or uses propane entirely. The only exception is if he was considering going off grid, but that won't be cheaper.

So the comparison really is at the $0.0699/kWh.



If it's a 2 stage heat pump and sized to keep up with the heat loss all the way down to that temperature. Most academic discussions I've seen consider sizing a system to -15F either putting a heat pump in an inappropriate climate, or oversizing it relative the typical conditions. Oversizing can hurt your overall efficiency worse than occasionally needing auxiliary heat.

With 2 other heat sources, I'd expect most installers to suggest a small single stage unit to keep their bid low.

No, that is just the generation charge.