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Can you have an accessory building on same plot as certified PassivHaus?

Kevin804 | Posted in PassivHaus on

I am designing a house with the potential of having an accessory flex building in the back of the lot. In order to be passivhaus certified do both building on the plot have to meet requirements or can I just make the main house meet requirements?

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  1. GBA Editor
    Martin Holladay | | #1

    I don't see any reason why you couldn't certify your house as a Passivhaus. After all, future plans shouldn't affect a current construction project.

    That said, the person to answer your question would be someone who has been certified as a Passive House Consultant.

    Here's the wrinkle: If you want two units on this piece of land, it would make sense (from an energy use perspective) to design a duplex from the start. But plenty of people do things that don't make sense from an energy use perspective.

  2. Expert Member
    Michael Maines | | #2

    Kevin, CPHC here. Yes, no problem with what you ask, assuming that utilities are separated, or fully attributed to the main house. You may be able to work with a certifier to allocate percentages of utility use to each building, but that gets tricky. You also have to take into account any shading that the accessory structure provides to the main house.

    That's per the original, international Passivhaus program. The American group, PHIUS, has their own set of rules, but as I understand it they largely align with the international standard. (You can certify through either PHI, the international group, or PHIUS, the American-only group.)

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