Is there a strong argument for using a bubble insulation or foil product on trusses instead of just a radiant barrier to reduce attic temps?
The house is average construction, built in 2008, with a very inefficient and arguably undersized HVAC system. I am trying to limit attic losses as much as practicable. I have a vaulted ceiling and am wrapping the existing framing/batt insulation with a double bubble-foil insulation. My current plan is to use the simple radiant barrier to cover the trusses and additional framing elsewhere in the attic. I have 12 inches (R-30) of CertainTeed blown-in insulation everywhere except for the cathedral ceiling framing. I am trying to conserve costs, but if I can expect noticeable results with the more expensive bubble barrier throughout I will do so.
A standard radiant barrier will perform just as well as the bubble-wrap radiant barrier. I would install this on the bottom of the rafter in a stick-framed roof or on the bottom of the top chord of the truss if you have a truss roof.
Prior to installing a radiant barrier, you should do the following:
- Air seal the ceiling
- Duct seal the HVAC ducts
- Bring insulation up to R-38.
These are cheaper and will give you a better payback than a radiant barrier.
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