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Community and Q&A

When to Hire an Energy Consultant

SamSam1 | Posted in Energy Efficiency and Durability on

I am building an ADU (1200 sq ft; plan attached). I want to make it as energy efficient as possible and strive for net-zero. Do you all think I really need an expensive Energy Consultant to do energy modeling, etc OR just go with my local T24 guy and just go all-electric and put high R insulators?

If there is anybody in this group, I would highly appreciate an honest reply from an Energy Consultant

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  1. Expert Member
    Malcolm Taylor | | #1


    An unrelated question: Why is your mid-wall bracing all wavy?

    1. SamSam1 | | #2

      I am not exactly sure about the wavy part you are talking about. Are you talking about the doors from all the three rooms?

      1. Expert Member
        Malcolm Taylor | | #3


        I'm sorry to hijack your thread - I was just curious. The mid-height blocking on your stud walls is just rendered strangely.

        1. wrrrgsp | | #5

          Blocking is likely staggered for easier installation. It lets you face nail each side. You can have them all in the same plane but then you have to toenail in one side.

          1. Tim R | | #6

            Malcolm - the staggered blocking was common in California track homes built in the 70's & 80" pre nail gun days. They also show on the plan let in bracing- not good in seismic areas. The designer might be a boomer.
            Back then the exterior finish was stucco, no sheathing just wires run horz. on the studs then grade D paper, lath & stucco.

  2. rajibroy | | #4

    I am NOT an energy consultant, but a Mechanical engineer; Currently working with Efficiency Vermont(state provided energy consultant), an Architect, and a Builder (well versed with energy efficiency) and a Lumber yard project manager (which also does energy efficient, LEED certified, large commercial projects) for a residential project. As you have noticed, it takes a team to get an energy efficient house.

    Things that I have learned embarking on home building:
    1. For any "energy efficient as possible and strive for net-zero", energy modeling is a must! One can do a whole house modeling using NREL software BEOpt, and a Manual J room by room HVAC load calculation.
    2. Your architect should give you some preliminary numbers on insulation strategy application to your climate zone and building plan. An energy consultant can work with the Architect to run the detailed analysis.
    3. For generic Energy Star house, your architect, or builder, or material supplier would be able to guide you common building envelop assembly for efficient house. For any sort of certification like "passive house" or LEED you might need an energy consultant. There is an state run agency in most state that advises on energy efficiency and is a great source.
    4. There is more to energy efficient house alongside insulation. Air tightness, HVAC duct-work strategy, building envelop design (external shading related to orientation, window glazing type, etc.). Without these details, just a high insulated house may not be energy efficient, may affect your comfort even!
    5. Mechanical design: I see the design is using ducted mini-split system, where the diffusers are next to windows. An energy efficient house can use compact ducted system with diffusers place in interior walls. For any ductwork, Manual D calculation is a must.
    5. I don't see any ventilation system such as ERV/HRV.
    6. Net zero usually involve some sort of solar PV, without energy modeling. How any project will estimate the amount energy to generate on-site?

    There are expert members here, and wealth of information in GBA. Hope this helps.

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