Question 1

What insulation generally has the highest R-value?

Accepted Answer

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Structural insulated panels and rigid foam boards have the highest R-value of any insulation that contractors commonly use, with R-values reaching up to around 8.0. These types of insulation are best in extremely cold climates, but they’re generally preferred for new construction, as they can be challenging to retrofit. Blown-in and loose fill insulation provide the next best insulative value, provided the installation is done properly. It’s important to choose an insulation type that meets your needs based on climate, as maximizing R-value may not always be financially worthwhile if you live in a moderate climate.

Question 2

Do I need to air seal my attic before installing insulation?

Accepted Answer

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Air sealing isn't necessary for attic insulation, but it's incredibly helpful since it can help you identify and patch any existing air leaks. Failing to find these leaks before adding insulation can render your insulation less effective, leading to higher energy bills and potentially costly repairs down the line.

Question 3

How long does it take to install a radiant barrier?

Accepted Answer

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Professionals can install a radiant barrier in a day or two, but DIY installation will take several days. The time it takes to install a radiant barrier depends largely on the size of the space and the installation method. Larger homes can take a pro two to three days to finish the job. It’s also quicker to lay foil over existing insulation.

Question 4

Should wall insulation be faced or unfaced?

Accepted Answer

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Unfaced wall insulation is easier to cut and install, making it the better choice for a DIY project. It’s also more affordable. But if it’s unfaced, you’ll likely need to add a vapor barrier to reach your desired R-value and efficiency, as it doesn’t offer any moisture barrier.

Faced insulation uses paper or foil to create a built-in barrier and doesn’t require an extra step. It’s also more fire-resistant and safe. But it’s quite a bit more expensive and a little bit harder to work with as a DIYer.

Question 5

Does basement insulation need a vapor barrier?

Accepted Answer

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Yes, basement insulation needs a vapor barrier due to its susceptibility to moisture seeping in from the outside of the house. You should install a moisture barrier before you install insulation or purchase insulation that comes prebuilt with a moisture barrier to avoid water damage in your insulation and costly mold and water remediation expenses.