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HVAC considerations for cathedral ceilings in Climate Zone 3?

dfloyd5646 | Posted in General Questions on

Martin, Dana (and regular contributors)

I’m refining details for new construction in CZ 3 that has a compact footprint and voluminous open first level, with cathedral ceiling, to enable superior day lighting.

Mechanicals are planned for walkout basement level.

With 22 foot interior height, have I painted myself into a HVAC system-specific corner?

Would like to use ductless mini-splits for reduced allergens, simplicity and efficiency.

When GC received 4 quotes from local HVAC reps, ductless MS estimate was $10k higher in install costs than traditional ducted system.

Is the design likely dictating the disproportionate added labor expenses, or am I possibly funding someone’s ‘crash course’ in ductless installs?

Thanks in advance for your time and assistance!

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  1. GBA Editor
    Martin Holladay | | #1

    We don't know the answer to your question unless you provide more information.

    1. Has anyone performed a Manual J load calculation? If so, what is the home's design heating load? What is the home's design cooling load?

    2. How many ductless minisplit heads does the contractor propose installing?

    3. Can you share the floor plan?

  2. user-2310254 | | #2

    David. Sometimes it is worthwhile to hire an HVAC engineer to evaluate your home and run an accurate Manual J. The engineer can help you spec the most cost-effective and efficient system for your home's actual loads. He or she also may be able to help you identify a few qualified local contractors and even interview the top candidate to verify that he or she understands the design requirements.

  3. Expert Member
    Dana Dorsett | | #3

    Without the load numbers on a room-by-room basis it's hard to say, but most homes can be cooled & heated with less than $15,000 worth of ductless equipment (installed), many under $10K, with judicious selection & placement of the ductless heads.

    If this is a "ductless head for every room" scenario it could indeed be paying for the contractor's yacht (marina fees included!)

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