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energy retrofit

Post in 'The Green Room' started by Billy123, Mar 17, 2013.

  1. Billy123

    Billy123 Member

    Joined:
    Mar 5, 2011
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    76
    Loc:
    PA
    Has anyone here done any type of energy retrofit?

    I was thinking, exterior foam sheathing, taped tight, would be the best bang for the buck along with attic sealing-insulating. Using used product even better.

    Some friend and I were talking about a stone faced home. My idea was exterior foam to the sides/back, and interior to the stone faced section, or, flash and fill?

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  2. GaryGary

    GaryGary Feeling the Heat

    Joined:
    Jul 12, 2010
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    291
    Loc:
    SW Montana
    Hi,
    I'd have a go at working out what your current heat loss is, and how much is due to walls, ceilings, windows etc. -- this might give you a better idea which areas need the work. A simple free calculator to do the heat loss:
    http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

    It seems like if you have access to the attic and its not already well insulated, that first sealing all the wire, plumbing, ... penetrations with Great Stuff and then blowing in cellulose is a no brainer cost saving. For me, doing the walls is going to have to wait until the siding needs replacement.
    Inside window insulating treatments seem like a good option.

    My favorite energy retrofit: http://www.builditsolar.com/Projects/SolarHomes/SchoolHouseRetrofit/Main.htm

    We've cut our home heating bill to less than half with a combination of attic sealing and insulation plus insulating window treatments and some solar thermal heating -- saving of about $2K per year in propane.



    Gary
  3. woodgeek

    woodgeek Minister of Fire

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    SE PA
    There is def a diminishing returns effect. The first reductions steps are almost trivial and dirt cheap to do, and then later it costs some coin to eke out a little more savings. The phrase 'deep energy retrofit' describes a 50-75% reduction in energy use, but costs 10s of thousands of dollars done professionally. A good energy audit and ~100 hours of DIY or pro work can usually nab 25-50% savings and have fast payback times.

    The attic airseal is a pretty easy DIY step....I did mine and am saving ~25-30% on my heat relative to before just from that alone. Not sure I could get a decent payback on exterior foam....with thin foam the savings might be a $100 a year, and with thick foam I would have to build out my windows, exploding the budget, but still only saving maybe $300/yr tops.

    If I were residing, I would def add as much foam as I could without messing with the window trim, but I don't expect foam would pay for the siding job.

    Compute your wall area in sq ft * 24 * HDD /R-value, and see how many BTUs you get. I have a 2300 sq ft house with 2x4 framing and crappy FG batts..I figure R-10 assembly value..and I am only losing ~12MBTU/yr through my walls by conduction. With the attic airsealed, I don't think I have a lot of airflow through the cavities.
  4. semipro

    semipro Minister of Fire

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    SW Virginia
    A lot of those that post in this forum have done energy retrofits to some degree. You'll get some good feedback on your plans.
    If you haven't already visited greenbuildingadvisor.com and buildingscience.com I'd suggest you do. They have some great info there on energy retrofits.
    I'd also suggest you consider having an energy audit done to establish a baseline against which your improvements can be compared. A blower door test with Infrared imaging can be incredibly helpful to identify how tight your house is, where infiltration problem areas are, and where thermal insulation is needed.
    I think the biggest realization that has helped me with my own efforts was that addressing air infiltration issues before addressing thermal insulation shortcomings provided the best return on investment as far as energy saved and living comfort..
    woodgeek likes this.
  5. semipro

    semipro Minister of Fire

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    If you go with exterior foam plan to install multiple layers, offsetting the seams. Foam shrinks and this helps prevent infiltration leaks.

    I have a stone and cedar siding house and have basically come to the conclusion that masonry belongs inside the house not outside it. As you alluded to, its more challenging to insulate masonry exteriors. Also the thermal mass on the inside actually does some good, not so much outside.
  6. EatenByLimestone

    EatenByLimestone Minister of Fire

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    I'm working on it little by little.

    Matt
  7. peakbagger

    peakbagger Minister of Fire

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    Most of the software that energy auditors use includes payback calculations so if if you have an energy audit done, the report shoudl show the best bang for the buck.

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