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Community and Q&A

Radiant Barrier in Climate Zone 3?

Matt M | Posted in Energy Efficiency and Durability on

I am considering a radiant barrier application in my attic. I have heard that a radiant barrier is most cost-effective in terms of return on investmentI when ducts are located in the attic. I have already removed my ducts from the attic and relocated them to my basement to improve efficiency. I get a ton of solar gain on my roof year round with very little shade during summer months. I wonder if this condition would make a radiant barrier a good application for my roof even without ductwork in attic.

Does anyone out there have an opionion/experience with a situation like this?


My conditions include:
Roughly 950 square foot surface area of ceiling.
R-30 insulation in attic is planned
Open lot with few trees, roof tops gains 5-6 hours of direct sunglight during summer months.

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  1. GBA Editor
    Martin Holladay | | #1

    If you don't have any ductwork or HVAC equipment in your attic, the most cost-effective measures to reduce summer heat gain through your ceiling are:

    1. Sealing air leaks in your ceiling, and

    2. Installing thicker insulation.

    Before you install your planned R-30 insulation, be sure that all leaks have been sealed (partition top plates, electrical penetrations, plumbing vent, chimney, attic access hatch, etc.).

    And if you have any money left over, don't spend it on a radiant barrier. Use the money you would have spent on the radiant barrier to buy thicker insulation.

    For more information, see Radiant Barriers: A Solution in Search of a Problem.

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