How often should you replace blown-in insulation?

Author: Mrs. Natalia Bartoletti V  |  Last update: Friday, July 18, 2025

Blown-In Insulation (Fiberglass And Cellulose) Because it is both efficient and economical, blown-in or loose-fill fiberglass is an insulation material that sees widespread use. In most homes, loose-fill insulation can survive anywhere from 80 to 100 years before needing replacement, provided that it is not damaged.

How long does blown in insulation last?

Under optimal conditions, blown-in cellulose insulation will last anywhere from 20 to 30 years. The lifetime of air blown-in cellulose is affected by a variety of factors, which is why it should be professionally mounted from the beginning.

Should you remove old blown in insulation before adding new?

Insulation needs to have room to expand to its full size to be effective, so the old definitely needs to be removed. Not to mention the old stuff is full of dust, probably some rodent excrement, and who knows what else that has accumulated in your attic over the years, so that's another reason to get rid of it.

How do you know if your insulation needs to be replaced?

8✔ COMMON SIGNS YOUR OLD INSULATION NEEDS TO BE REMOVED
  1. Fire damage.
  2. Water damage.
  3. Higher energy use than usual.
  4. Rodents getting up in the loft messing up the insulation.
  5. Hazardous old insulation that has the potential to have asbestos in it.
  6. Insulation squashed by storage boards, slumped insulation.

Is it worth replacing blown insulation?

If you live in an older home, it may be time to remove your old blown in insulation material. A proper replacement will help lower utility bills, retain the value of your property, and keep you and your family comfortable all year round.

When Should You Remove Old Attic Insulation?

Should I replace 20 year old insulation?

However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.

What is the disadvantage of blown-in insulation?

Cons of Blown-In Attic Insulation:

Poor installation can lead to uneven coverage, material waste, and even structural issues like sagging ceilings. Hiring a skilled installer is crucial to getting the most out of this insulation type.

How much does insulation replacement cost?

The average U.S. homeowner spends about $1,852 to install insulation. Depending on the type of insulation, square footage, site location, and material, you might spend anywhere from $498 to $4,500. Insulation can keep your home cozy and warm on long winter nights or cool and comfortable on hot sunny days.

How often should attic insulation be replaced?

However, due to its construction with natural materials, eventually the product will lose effectiveness. Fiberglass insulation typically needs to be replaced 15-20 years into it's life, as it can easily become dirty, wet, moldy, and ineffective if there's a roof leak or water damage of any kind.

Does replacing insulation increase home value?

The short answer is yes, upgrading insulation can increase the resale value of a home.

What can I do with old blown-in insulation?

Call your local waste-management office and ask what to do with the insulation of your type. In some cases, you can place the bags out with your regular trash. In others, you will have to take it to a designated area at the dump.

Can you have too much blown insulation?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

How much does blown-in insulation cost?

The cost to install blown-in insulation depends on the type of insulation you choose for the project. Anticipate spending anywhere between $0.50 and $2.30 per square foot for materials, not including installation.

Should I remove old blown in insulation?

Insulation is more than just material. It's about creating a healthy, efficient, and comfortable living space. Removing old insulation might seem like an extra step, but it's a leap toward better air quality, increased efficiency, and peace of mind. So, when you're looking to upgrade, don't just add—replace.

Is it OK to touch blown in insulation?

Unlike blown-in fiberglass, blown-in cellulose is safe to touch with bare hands. While your hands may come away dusty, contact dermatitis is not a risk when touching ground-up paper.

What type of blown-in insulation is best?

Fiberglass is by far one of the most thoroughly tested building materials and can be installed in the form of batt or blown-in insulation. Fiberglass is eco friendly, non-flammable, safe to install and maintains its thermal performance for the life of the building.

Does blown-in insulation go bad?

Blown-in insulation typically lasts for about 20 to 30 years. Proper installation and conditions can extend its longevity. Choosing the right insulation for your home is crucial for energy efficiency and comfort.

How do you tell if your attic is properly insulated?

Looking across your attic, if the insulation is level with or below the attic floor joists, you probably need to add more insulation. If you cannot see any of the floor joists because the insulation is well above them, you probably have enough, and adding more insulation may not be cost-effective.

Can an attic be too insulated?

Too much insulation will leave humidity and moisture to accumulate in your attic space. This can lead to mold growth on your walls and insulation. There might also be water damage to the support beams in your home's roof.

What is the best type of insulation for an attic?

Fiberglass batt is considered to be the best insulation for attics. Compared to other insulation materials, it is the cheapest and easiest to install.

Can you put too much blown insulation?

Can you over insulate your attic? The answer is yes! Past a certain point, insulation in a vented attic will do more harm than good. In most of the United States, achieving an R-Value of 38 is more than sufficient.

What is better blown in, cellulose or fiberglass?

Both cellulose and fiberglass are energy-efficient insulation materials, but cellulose has a slight edge due to its higher R-value. The R-value for cellulose insulation is approximately 3.2 to 3.8 per inch, while fiberglass insulation typically has an R-value of 2.2 to 2.7 per inch.

Is blown in insulation bad for your lungs?

Blown-In Cellulose Particles Are Paper.

Unlike glass fibers, cellulose isn't dangerous to breathe. However, it can irritate your lungs. If you have pre-existing allergies, the dust of cellulose insulation can be obnoxious.

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