Question 1

Should you remove old insulation before adding new insulation?

Accepted Answer

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You do not always need to remove old insulation before adding new. If the existing insulation is in good condition—not wet, physically damaged, moldy, or infested with pests—you can add new insulation directly on top of it for a compounding effect. You can also mix different types, such as adding blown-in insulation around existing fiberglass batts.

However, removal is recommended if the old insulation is compromised by water damage or pests. You should also remove it if you plan to install a different type of insulation, like switching from roll or batt insulation to spray foam. If the existing insulation is very old or damaged, you will likely get more benefit from removing it and starting fresh.

Question 2

How long does duct insulation last and when should it be replaced?

Accepted Answer

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Air duct insulation typically lasts for 10 to 15 years or even longer, depending on the material and maintenance. It's important to conduct periodic inspections to check for signs of deterioration, such as water damage, tears, or general wear. If you find any of these issues, it may be time for repairs or a full replacement. You might also consider upgrading your insulation even if it's in good shape to improve your home's energy efficiency and enhance your HVAC system's performance with newer, more effective materials.

Question 3

Are there sustainable insulation options for attics?

Accepted Answer

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Yes, including recycled denim and cellulose from natural fibers.

Question 4

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.

Question 5

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.