Sea Glass

Sea Glass

Tuesday, March 23, 2010

Leaking by design

Leaky Attic?

We can spend a lot of money on technology that improves efficiency and gets to showcase some cool toys. But nothing beats just having good design.

Do you have a house where the insulation is laying against the ceiling drywall and there’s a big old attic above where your ductwork lives? There’s probably a bunch of recessed lights and other things penetrating the ceiling drywall and anyone who’s had the fun of crawling around in a Florida attic knows that the insulation doesn’t really seal all that well like it should.

Most air ducts leak, some a little, some a lot. When you have leaky ducts in the attic described above, guess what the air leaking out of the ducts does? As the air is being drawn out by the air handler and some leaked into the attic, a negative pressure field builds up in the house. A negative pressure field draws attic air not just into interior framing but also down exterior walls, adding humidity as it goes. It also picks up contaminants. There’s also humid air coming from every conceivable opening your house, be it doors and windows, mysterious holes in the slab, etc. The end result, besides inefficient AC, is discomfort, mold, and all the problems that eventually come with damp building components.

Is there an easy fix? I say yes. Just change the attic from an unconditioned space to a conditioned space by installing an open cell or closed cell foam insulation system to the underside of the roof deck and making the attic “unvented”. This puts the air distribution system within the conditioned space and reducing the major adverse effects of system leakage. This also improves the durability of the AC equipment and ductwork and adds to the efficiency.

Give us a call if you need more information.

Jeff Good
Benchmark General Contractors, Inc.

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