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What is the largest category of heat loss in a standard California Title-24 house located in the Sacramento-San Joaquin valley?

bonnie matheson | Posted in Energy Efficiency and Durability on

What is the smallest category?
Air Infiltration, Windows, Slab Edge, Wall, Ducts, or Ceilings?

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  1. GBA Editor
    Martin Holladay | | #1

    Perhaps someone familiar with "typical" new house construction in this area can respond.

    I think it's important to point out, however, that there is no single answer to this question. Many different styles of house can be Title-24-compliant. It's possible for a house with many windows to comply with Title 24, and it's also possible for a house with very few windows to comply with Title 24. Each house style will have a different answer.

  2. sheeschen | | #2

    The answer to such a question is always "it depends". As Martin points out, Title-24 compliance can be achieved in many different ways. I do have a rough datapoint, however. I'm entering my remodeled house into PHPP (a passive house spreadsheet) to figure out if I need to spend extra money on getting fancy, super-energy-efficient windows or not. I'm still learning about the program, but so far have realized that I lose about the same amount of heat through my windows as through my (walls+ceiling). Energy lost through ventilation, air infiltration, and that ilk is about 1/10 of the heat lost through (walls+ceiling+windows). I'm in the San Jose area, and my walls and ceiling are going beyond the standard title-24 requirements, but not hugely so (R-24 walls, R-35 ceiling). Most of the windows are kind of standard, but some are expected to be highly-efficient (R7 or so). The Title-24 report had me passing with about a 40-50% margin, but I believe the ratios of where the heat is lost would remain about the same. Anyways, it's a datapoint.

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