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Recommended insulation level in commercial buildings

Curtis Dean | Posted in Energy Efficiency and Durability on

What are the recommended R values for insulation in a commercial building that is conditioned? I am in Spencer, Iowa so that would be Zone 6.

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  1. GBA Editor
    Martin Holladay | | #1

    You should contact your local building code official to determine the code requirements in your local area.

    According to the 2006 IRC, residential buildings in Zone 6 need a minimum of R-49 ceiling insulation, R-20 wall insulation, and R-30 floor insulation. Whether the building is commercial or residential, I wouldn't recommend less insulation than the code minimum.

    More is better.

  2. Riversong | | #2

    The IECC standards are in Tables 802.2(1) through 802.2(7).

  3. Riversong | | #3

    This link is to a DOE manual for inspections for the commercial provisions of the IECC:

  4. Armando Cobo | | #4

    Look at the 2009 IECC, Chapter 5. Table 502.1 gives you the Building Envelope Uvalue for a particular building method (metal, metal framed or framed). Table 502.2 gives you the Rvalues for same. You should be familiar with the whole Chapter 5 as there are many other parameters and requirements for commercial buildings.

  5. J Chesnut | | #5

    Ideally a developer thinks in terms of an energy goal and then determines the R-values, air tightness, window specs, and mechanical specs needed to meet that goal. PassivHaus principles are being applied to small to mid sized commercial buildings (office and school buildings) in Europe.

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