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Community and Q&A

How to insulate attic furnace?

John Sean | Posted in General Questions on

I have an furnace in an attic, where the rest of the attic is not finished.

The builder put 2×3’s around it with some 1/2″ polyiso boards.

What is the best way to insulate this thing?

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Replies

  1. Steve Knapp CZ 3A Georgia | | #1

    John,

    Where are you located? Is this new construction?

  2. Walter Ahlgrim | | #2

    Putting the HVAC ducts and equipment in an unconditioned space like attics and crawl spaces is a bad idea if you are paying for the fuel, but it great idea if you are selling the house. Because no one wants to pay for a utility room, make the same space a bathroom and 10k to in your pocket.

    If it is too late to put the equipment inside the thermal boundary the only real solution move the thermal boundary from the ceiling to the roof.

    Please take the time to read this article
    https://buildingscience.com/documents/published-articles/pa-are-you-doing-somethig-stupid/view

    Walta

  3. John Sean | | #3

    Yeah I never understood this. Don't the baffles let in outside air anyway?

  4. Steve Knapp CZ 3A Georgia | | #4

    John,

    If the system uses combustion to create heat, it has to have an air source. Sealed combustion is better than atmospheric combustion. But Walt is right, the best solution would be to move the system and ducts inside the conditioned space.

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