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Community and Q&A

Energy calculations for residential construction

Dunepray | Posted in GBA Pro Help on

Greatly in need of assistance.
I will be the Owner/Builder and constructing a new home in the Kern County/Southern California area. I’ve nearly completed (I HOPE) the design drawings and code compliance criteria with exception of an energy calculation(s) requirement which the Inspector says I must complete (They sure are hard to contact during these times).  I’ve completed voltage plans in the past, however, I am unsure if there is a designated design criteria involved for completing energy calculations.  My online research leads me to the typical usage spreadsheets (which I think are fine).  I’ve gathered all appliances energy usage numbers and looked for calculators/spreadsheets online.  My large problem is that some of the websites I’ve tried appear to be less than reputable.

Any guidance would be greatly appreciated.


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  1. walta100 | | #1

    My wild guess is the inspector is looking for a manual J calculation. In my opinion a manual J calculation is a good idea but getting accurate is a lot of work. Many HVAC contractors will give you a free manual J calculation that will satisfy the inspector. In my opinion 99% of theses are worthless and leading you to install 2 or 3 times larger equipment than desirable. Like most things you get what you pay for.

    I thought I read somewhere that all new CA homes were required to have solar panels installed. If so there will be several calculations required.


    1. Dunepray | | #3

      Thanks Walter,
      I agree. With everything I've learned over the past couple years while designing this build I have decided to go with Mitsubishi mini-splits and Lunos E-Go and E2 venting for HVAC. Simple, efficient, and I think cost effective.
      As for solar, the earlier requirement has changed slightly and does not require solar, however, I am designing a solar grid-tied system and including that with my plans submission.

  2. Expert Member
    Michael Maines | | #2

    Many places require a ResCheck, but California has its own set of rules.

    1. Dunepray | | #4

      Thanks Michael,
      I'm going to try it.

      1. Dunepray | | #5

        As it turns out ResCHECK map link shows California not compliant with their version.


  3. GBA Editor
    Martin Holladay | | #6

    You'll need to be sure that your plans comply with California's Title 24. If you aren't well versed in the code, you should hire a Title 24 consultant to help you.

    1. Dunepray | | #7

      Thanks Martin,
      I believe when all is done on my end I will bring everything to an engineer and Title 24 consultant. It will make plans go a little smoother.

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