The right basement insulation is key to a comfortable, cozy home all year long
Insulation can help regulate your basement's temperature, potentially saving you money on your monthly energy bills without sacrificing year-round comfort. Insulation also helps soundproof your basement, blocking outside noises for you and preventing your neighbors from hearing what's happening inside your household.
The best insulation for your basement depends on several factors, such as whether you're insulating your basement ceiling or walls. This guide outlines different types of basement insulation to help you choose the right type for your needs.
Understanding insulation R-values can help you choose the best insulation for your basement. R-values indicate how well different insulation types prevent heat from leaving your home, making it a good overall measure of effectiveness. The higher the R-value, the better the insulation keeps heat inside.
Typical R-value: 3.5–8.0
Foam board insulation comes in rigid sheets made of polystyrene or polyisocyanurate, and you can use it in both basement ceilings and walls. It's relatively inexpensive and easy to install —especially when installed before framing the walls—so it's a great option for DIYers on a budget. Foam board insulation is also low-maintenance and moisture-resistant, which is why it’s basement-approved.
Perfect for walls and ceilings
Moisture-resistant
Low-maintenance
Easy to install
Inexpensive
Air bubbles in polystyrene can accumulate some moisture
Must be very precisely cut to work effectively
Made of polyurethane, you can spray foam into small crevices, at which point it expands to fill the area completely. Spray foam insulation is ideal for filling remaining ceiling or wall cavities, such as gaps between wall studs. It doesn't retain moisture, so it won't cause mildew or mold, and it has strong sound absorption properties. However, spray foam insulation costs more than other insulation types.
Easily fills small gaps and crevices
Doesn't retain water
Strong sound absorption capabilities
More expensive than other insulation types
Not ideal for insulating large spaces
Typical R-value: 3.1–3.4
Fiberglass insulation is made of tiny glass fibers. It helps to regulate interior temperatures and offers strong soundproofing capabilities. However, it's not generally recommended for basement walls because it holds onto moisture, leading to water damage, mold, and mildew. But it can work well for insulating the basement ceiling when the basement isn't prone to moisture.
That said, fiberglass insulation is hazardous to your health if touched or inhaled, so you should always wear proper safety gear if you're handling it.
Excellent soundproofing capabilities
Doesn't retain water
Relatively inexpensive
Hazardous if touched or inhaled
Retains moisture
Not recommended for basement walls
Typical R-values: 3.1–3.4
Mineral wool insulation is a common alternative to fiberglass. It boasts a higher R-value than fiberglass, and it's often made from 30% recyclable materials. It's also moisture-resistant and can slow the spread of fires in the home, so it's ideal for basement walls and ceilings. However, it's typically more expensive than fiberglass.
Good for walls and ceilings
Made with recyclable materials
Higher R-value than fiberglass
Moisture- and fire-resistant
More expensive than fiberglass
Tougher to install than some other insulation types
Typical R-values: 3.2–3.8
Cellulose is a thick and dense loose-fill insulation derived from plant sources. It's usually composed of recycled paper and cardboard, making it more eco-friendly than other types. Cellulose is affordable and has a relatively high R-value, but it's not as moisture-resistant as some other insulation types, so it might be a better fit for basement ceilings than walls. It can also pack down over time, creating thermal bridges that move hot and cold air around, reducing its efficacy.
Affordable
Made of the most recycled materials out of all insulation options
Boasts a Class 1 Fire Retardant Rating
Higher R-value than fiberglass
Possible to install yourself
Less moisture-resistant than other insulation types
Might pack down over time, creating air leaks that minimize its efficacy
Not considered the best option for walls
When choosing a professional insulation installer, consider asking these questions to determine the best fit.
Will you address air leaks in my house?
Can you provide an R-value (heat resistance) fact sheet?
What kind of insulation will work best for my home?
How do you handle signs of a water leak?
Are you licensed and insured?
Can you provide customer references?
The best type of insulation for your home depends on what you need, so the answer will depend on your specific situation. If you’re building a house, structural panels are easy to install during the building process in addition to being the most energy efficient type. If you live in a warm climate, reflective insulation may benefit you more as it costs less than other insulation types. And for standard attics, loose-fill, spray foam, or blown-in insulation work well.
If you plan to heat or cool your garage, you’ll need to insulate the garage ceiling. Insulating your garage ceiling will make your garage much more energy efficient and save on heating and cooling costs. Not only does insulation make your garage more energy efficient, it helps reduce noise and can extend the life of your garage roof. You can use fiberglass, cellulose, mineral wool, or spray foam insulation for this project.
In some cases, you may not have enough insulation to properly regulate your home’s temperature. Watch for a few signs your home needs more insulation, such as:
High heating and cooling bills
Uncomfortable room temperatures
Ice dams on the edge of your roof
Roof leaks
Cold floors and walls
Freezing pipes
Temperature fluctuations
Visibly low insulation
Noise problems
Pest problems
On average, insulating an attic costs about $2,500, ranging from $1,500 to $3,500, depending on the insulation type, amount, and your attic’s accessibility. Additional cost factors include sealing air leaks, removal or replacement of insulation, and inspections. Types of insulation include:
Blown-in: $1–$4 per square foot
Spray foam: $2–$5 per square foot
Batt: $2–$4 per square foot
Structural insulated panels: $4–$7 per square foot
Loose-fill: $2–$5 per square foot
Reflective: $0.50–$1.50 per square foot