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Local cost per million btu's

Post in 'The Inglenook' started by fox9988, Aug 9, 2012.

  1. fox9988

    fox9988 Minister of Fire

    Joined:
    Jan 15, 2012
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    NW Arkansas
    Sorry, I'm not the most organized. And like I said not my profession. I believe it but, am not the best person to defend it.

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  2. woodgeek

    woodgeek Minister of Fire

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    Jan 27, 2008
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    SE PA
    COP is COP. A COP of 2 means it delivers two units of (heat) energy for every unit of (electrical) energy you put in. The way they are built, the electrical energy input also ends up as heat (what else?), so if COP = 2, it pumps one unit of heat from some source, and the other unit comes from the grid. At COP = 3, 2 units get pumped from the outside, and 1 comes from the grid etc.

    In a BTU cost calculator, put in eff%=COP*100 to the electrical box to get the BTU cost.

    Tech has improved a lot. Cheap air-source HPs nowadays have a COP = 2.3 or so at 32°F, falling to 2.0 by 20°F or so. Good enough in my climate and milder. Minisplits and high-end HPs ('greenspeed') get about COP ~3 at 32°F, and geos get nominally ~3.5 at all temps.

    Many folks give these units a bad rep, mostly due to experience with older units, bad installs or both. The whole 'don't work below 32°F' line is outdated. For a bad install, take a full point off the COP numbers above (geos included).
    fox9988 likes this.
  3. fox9988

    fox9988 Minister of Fire

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    581
    Loc:
    NW Arkansas
    Yeah, NG or a HP could be tempting. I am all about wood heat, that's why most of us are here.
    A friend of mine owns a lake house that sits vacant most of the winter. He switch from resistance heat to a HP and his bill went down from $100 to $60 per month. Allowing the service fees, taxes, etc., that's quiet a reduction. For the record, he does have a wood stove that he uses when he's there.
  4. fox9988

    fox9988 Minister of Fire

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    NW Arkansas
    Danno, you can't count the saws, truck, splitters,etc. Those are your toys/hobbies/pacifiers. I'm sure your wife would understand if you just explained it all to her()::P
  5. velvetfoot

    velvetfoot Minister of Fire

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    fox9988 likes this.
  6. fox9988

    fox9988 Minister of Fire

    Joined:
    Jan 15, 2012
    Messages:
    581
    Loc:
    NW Arkansas
    Nice calculator. I forgot coal, no longer available for me. Until the ealy '80's it was locally mined and commonly used around here.
    NG $.36-$2.95, big differance.
  7. StihlHead

    StihlHead Guest

    Yah, the last energy calculator is typical of several of that I have seen. Wood heat here is cheaper than any other option, and I get my wood mostly for free. I had a heat pump priced here and the payback return vs. plain electric furnace was 10 years. Compared to wood it would be 30 years, even if I paid $175 a cord for firewood. So I bought a new 30-NC wood stove, for far less $$$ than a HP.

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