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What are the hard costs to go from a HERS 90 to a HERS 70 in Climate Zone 5B

kim_shanahan | Posted in Building Code Questions on

Our county is considering creating a Energy Efficiency requirement of a HERS 70 on all new residential construction. If we follow the IECC 2009, which our state has adopted, the prescriptive path is presumed to achieve a HERS index of 89. The question posed is how much more it will cost a builder, including HERS analysis, testing, and verification, to get to a 70.

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  1. bxxKT22MVd | | #1

    rough answer is 5-10x what the state tells you. don't forget the testing charge too.

  2. jbmoyer | | #2


    With good design the costs are minimal. With bad design, the costs could sky rocket.

    Builders can easily build AFFORDABLE homes that reach HERS 70. If they can't, they should get out of the business.

  3. Expert Member
    ARMANDO COBO | | #3

    I agree with Brett. If you have an experienced team working for you, you should not see any cost increase at all, or worst case, a very minimal increase; and if you do a life cost analysis, then it becomes cheaper. It’s all about reducing costs in some areas to pay for the increase in others.
    You also need to sell a more comfortable, less maintenance and healthy home to yourself and/or your clients… what is the price of that?

  4. jbmoyer | | #4

    Exactly Armando!

    HERS 70 and lower homes are more comfortable, durable, healthier, safer, etc.

    You MUST sell these benefits. I tell my builder friends that if you do anything above and beyond code, you BETTER sell it.

    And you should also convey to your potential buyers that a code-built home is a D minus on a building report card.. Homeowners (and builders) need to realize that codes are not in place to push for A+ homebuilding. They are there to establish a minimum bar. Anything less than code is ILLEGAL.

    So if you can't do any better than a D minus, 2x6 wall with an R-19 batt in climate zone 5, you as a builder should be ashamed of yourself.

  5. kim_shanahan | | #5

    Thanks for the feedback guys, but you are preaching to the choir. Our HBA is pushing for the HERS 70 requirement, but many in our County (the foot-draggers) are saying it will add 5% - 6% to the cost of construction. We are say it is more like 0% - 1%, but we need hard numbers. Anybody got 'em?

  6. Expert Member
    ARMANDO COBO | | #6

    I would think it'll be really hard for a builder to “duplicate” green costs based on some other builder's costs. It’s all different when you look at material and labor prices from vendors to vendors and subs to subs, even within the same town or metro area. It has to do with availability of materials and labor with in a market. It also has to do with differences in sub’s knowledge and experience or lack of it. It has to do how strict is a builder with their building techniques and waste in materials; and even has to do with good sets of plans versus plans without details and information. It all plays a part on how builders get their costs. If you give two builders the same house plan in the same town, more than likely they’ll have different costs associated all the issues stated above.
    A good answer can be given by national production builders who typically build and sell the same house plans many times over, and most of those same plans were built before they “converted” them to green homes. If you look at the statistics from NAHB and the Production Builders Council members, some say they have achieved 30% energy efficiency for no cost, some for 1-3% extra and some for more than that. I would suggest you investigate with some of them.
    You guys in Santa Fe have a unique market that it would be very difficult to compare to most cities in the country, and specially compared to big markets where most big production builders are building.

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