AFUE, HSPF and COP, how do they relate?

[johnbartley]

me to calculate heat pump heating efficiencies based on the AFUE of the heat pump, but I see them measured in HSPF (Heating System Performance Factor) at the state website which discusses rebates Other USENET discussions (here and elsewhere) discuss a third measure, the COP (Coefficiency of Perfomance).

Are there conversion factors from one to the other? Given one, how can I calculate the others?

If there is none, is there an alternate web site I can use to estimate the result if I replace a gas furnace with a heat pump?

Thank you kindly.

-- K7AAY John Bartley Portland OR USA views are mine, all mine.

"The Temporal Office says you have to do this. No, no explanation. Here's your stuffed tuna and an airhorn." - James Nicoll

[Travis Jordan]

Guess the search engines are down again?

[johnbartley]

Found the aforementionsed site, plus others, but they are either opaque (don't reveal how they calculate... which, after the flap over the bad 'hockey stick' model that was used to justify Kyoto makes me mistrust them, as they are probably assuming we run our house hotter than we do, our house is less well sealed than it is, or it's larger than it is) or ask for data in arcane formats (i.e., AFUE for heat pumps).

Also, a search for the conversion factors themselves was not productive.

I did my homework first.

[PrecisionMachinisT]

Suggest take a *good* look at some typical heat pump performance charts that show outdoor temperatures v/s btu output, and charted along with compressor draw before attempting to give advice.

[PrecisionMachinisT]

You do realize that you don't have drill until you "hit water" in order to use geothermal......

[PrecisionMachinisT]

Which kinda begs the question....

Didja happen to ask him about horizontal well drilling ???

[johnbartley]

Yes. However, he said he was likely to hit basalt within 50', which makes even the design here impractical:

[PrecisionMachinisT]

Direct exchange system....

Im guessing you near the west hills else maybe down towards Oregon City........... some hard rock in both those areas for sure....

The Troutdale aquifer is all sand, and is a perfect area for geo....oh well.......( pun not intended )

I use all heat pumps, an easy choice since nat gas isnt readily for me and i dont feel like bothering with propane........

My brother is up north of here, nearer to Seattle, and he uses a heat pump with gas backup...his having gone through this process just a few years ago...and so so if I was to advise, I would suggest you should consider doing the same--that way you can always change over your primary heat source depending upon what the fossil fuel v/s electricity prices do in the future......and since you are looking 15 years out and all.....that's just too long a time span, IMO--and so it becomes more like gazing at a chrystal ball than it is making accurate economical decisions...anybody's guess.....

[PrecisionMachinisT]

30 F usually aint bad at all...sized properly, heat pumps generally work fine in that temp.

But, this doesnt really belong on alt hvac, so best would be to take it offline as I dont follow the other groups you are crossposting posting to.....feel free to email me for more info if you like--my email address is good.