My wife needs convincing …
fitchplate
| Posted in General Questions on
You all have me convinced that I can change out my Mitsu AC minisplits with some all season heating and AC cold climate heat pumps and save substantially on the energy costs over my 98% efficient boiler.
But my wife is not convinced.
Are there objective data or honest reporting about the feel of living with CC-AHP’s in the 5a/6 climate of the south side of Lake Ontario. I am sure it’s better than traditional forced air, with modulated and instant adjustments to maintain steady no-hot-cold cycling. But we are not sure if the rave of these units is operating cost driven only whereas the comfort in a cold climate might be compromised.
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Replies
What does your wife have to do with this technical and economic decision ??
:p
What do you pay for electricity, and what do you pay for propane?
The -FH series Mitsubishis will probably average a COP of about 3.2+ seasonally in your climate. The -FEs will run about 3.0. That would be about 11,000 BTU/kwh with the FH, 10,000 BTU/kwh for the FE.
The 98% efficiency boiler delivers about 89,000 BTU per gallon, but the system also uses electricity.
So, with the FE you're looking at a 8.9 kwh to displace a gallon of propane.
With the FH you're looking at 8.1 kwh to displace a gallon of propane.
At 30 cents/kwh (I recall your winter rates are about that high?) that's equivalent to $2.40- 2.70/gallon propane. That would be a significant discount from average propane prices in MA (which have been running $3-4/gallon for the past 5 years), but propane markets vary- a LOT, by both location and over time, and may not be any kind of discount for you this year:
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=W_EPLLPA_PRS_SNY_DPG&f=W
If your shoulder season electricity rates are lower than that or if electricity price moderate after NY gets through re-shuffling the grid-regulations deck there may be a discount, but there is nothing quite like doing the math, eh?
Even if the marginal operating cost is lower, whether it ever "pays off" on reduced operating costs over it's lifecycle is another factor to consider. You need a fairly un-clouded crystal ball on energy price futures to make that call, but it's unlikely that propane will stay as cheap as it is right now forever (since it's part of what is paying for the costs of fracking, along with light-tight oil and other liquids, not the natural gas), and over the intermediate & long term I would expect NY electricity prices to be substantially below current prices (which are higher than the lifecycle cost of new PV solar, and almost at parity the lifecycle cost of solar + batteries!) You may want to play "wait and see" for a year or two, to see which way it breaks, given just how up in the air the electricity market regulations are in NY state right now. If they screw it up you could see even steeper electricity prices in the near term, if they do it right it should moderate fairly quickly.
Google this article and all your questions will be answered ...Cold Climate Air Source Heat Pumps
Results from Testing at the
Canadian Centre for Housing Technology...regards,Bob
I'm not sure why Bob didn't include the link -- but here it is:
Cold Climate Air Source Heat Pumps - Results from Testing at the Canadian Centre for Housing Technology
Because I am technically challenged ..lol..
Yes, the kwh price was 30 cents a month ago; now its down to 27.6 cents. According to NYERDA, the average price for propane in western NY is around $2.43 right now. Big drop from last year.
You're no fun! My wife will be happy to read your post, Dana ... that is if I tell her about it :-). I thought it would be more compelling economically. So her concern for the discomfort of air blowing out of those wall mounted splits will now weight more heavily on the scales.
Back to PV's for a while.
The "light warm summer breeze" coming out of a ductless head is not a comfort problem, since the typical temps of the exit air is above 115F, and the velocity (= wind chill) quite low except when running full-blast (which will usually be in the pre-dawn hours before you get up.)
Her concern may arise from the fact that some ducted air source heat pumps normally run a tepid 90-100F air at the registers, which can be uncomfortably cool at higher cfm due to the wind chill effects.