Ducts In Conditioned Space

DATE: Apr 25, 2014

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{The two photos illustrate the closet and the truss joists.}

100% of duct work in the Glavin Homes’ Parade house is in conditioned space. What does this mean and why does it matter?
First, let me explain the typical duct work in 99% of houses, new and pre-owned. The furnace is located in the garage. The duct work immediately goes under the house and into the crawlspace and also goes up into the attic. Both of these places are unconditioned. In the winter, the air in the ducts immediately start losing heat. In the summer the air starts heating up. Ducts have about an R7 insulating factor. This is quite low. By the time the heated or cooled air travels the length of the house, either in the crawlspace or the attic, up to 50% of the energy required to heat or cool the air has been lost. Wasted, never to return.

If all of the duct work is in conditioned space none of the energy is wasted. How is this accomplished? The first step is to move the furnace into a conditioned space. Glavin Homes typically places it upstairs in a furnace closet. The furnaces we use are highly efficient and quiet. Noise is not an issue. The second important item is to use a truss joist instead of a solid joist. This allows the duct work (and also plumbing and electrical) to be run through the joists without having to drill holes in the joists. The ducts can also be large enough to allow the free flow of air. This definitely costs more money. But, we believe that it is money well spent.

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