Climate Zones in Colorado and the International Energy Conservation Code – Insulation R Values

The International Energy Conservation Code is increasingly the standard energy code that municipalities are adopting. In prescribes insulation (r-value) requirements for both residential and commercial buildings.

In order to determine what your required insulation values are, you must first determine which of the climate zones you fall in. In Colorado it is highly dependent on the county and we actually have 4/8 zones present in the state.

Baca, Las Animas and Otero Counties are in Zone 4.

Alamosa, Archuleta, Chaffee, Conejos, Costilla, Custer, Dolores, Eagle, Moffat, Ouray, Rio Blanco, Saguache and San Migual are in Zone 6.

Clear Creek, Grand, Gunnison, Hinsdale, Jackson, Lake, Mineral, Park, Pitkin, Rio Grande, Routt, San Juan and Summit County are in Zone 7.

The remaining counties are in Zone 5.

Once you have the Zone and the construction type, you can consult the charts to determine the insulation requirements for each assembly. The various options are too numerous to list without simply posting the code. If you have any specific questions or need a list of counties outside of Colorado, comment on the post or email me.


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4 thoughts on “Climate Zones in Colorado and the International Energy Conservation Code – Insulation R Values”

  1. Marjorie, generally speaking there are fire and sound separation requirements between units, but not energy requirements for insulation. Why do you ask?

  2. Hi,

    My daughter owns a condo in Denver, Colorado and I need to know the R-value for insulation between units? Currently, there is no insulation between her unit and the unit above her.

  3. Tom, I enjoyed speaking with you earlier. Based on a commercial building in Zone 5 it looks like the continuous insulation over the deck could be R-20. With tapered rigid in Denver the building department has usually allowed us to average the thickness to achieve the necessary value.

  4. Locations is downtown Denver

    I need to know the minimum R-value required for a 14 story residential building; rigid insulation over concrete post tension slab over occupied space.
    Thank you,

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