Should you remove old blown-in insulation before adding new?

Author: Dr. Reynold Hoeger DVM  |  Last update: Sunday, July 20, 2025

If your home's insulation has reached the end of its life span, you may wonder: should you remove old insulation before adding new? Fortunately, in most cases, you don't have to remove old insulation before you add a fresh layer.

Do I need to remove old insulation before blowing in new insulation?

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.

Do insulation installers remove old insulation?

Any reputable insulation installer will thoroughly remove old insulation before putting in the new. However, as a homeowner, you should double-check that they remove all of the old insulation as a first step.

Should I remove old roof insulation?

Condition of Existing Insulation: - If the old insulation is in good condition (not wet, moldy, or damaged), it may be acceptable to leave it in place. However, if it shows signs of deterioration or contamination, it should be removed.

Should I get rid of old insulation?

Before installing new ceiling insulation in your home you should consider removing any old existing loosefill insulation or insulfluf which might have become contaminated with vermin faeces and urine or just simply have broken down over time.

Should I remove old insulation before adding new

Is it worth removing old insulation from an attic?

Benefits of Replacing Your Attic Insulation

Enhanced energy efficiency: New insulation can help reduce energy costs by improving your home's ability to mitigate thermal transfer. Indoor air quality: You can improve the air quality in your home by removing old insulation that may harbor mold, dust or allergens.

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.

Can I add new insulation on top of old insulation?

In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.

How do you remove old blown insulation from an attic?

How to Remove Blown-In Insulation
  1. Inspect the Insulation. There are several different types of insulation, so you should first identify the type you have in your attic. ...
  2. Gather the Right Equipment. ...
  3. Protect Your Space. ...
  4. Create Your Workspace. ...
  5. Set Up Tarp and Trashbags. ...
  6. Put on Safety Gear. ...
  7. Vacuum Insulation. ...
  8. Clean Up.

How often should roof insulation be replaced?

As a general rule, insulation should be replaced or retrofitted every 15 to 20 years. However, it may need replacing or retrofitting sooner depending on the type of insulation installed, the R rating of the original insulation, compression and movement over time, and whether any damage has occurred.

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.

How do you dispose of blown in insulation?

Get Dumpster Service Near You
  • Reuse Your Materials. There's no rule that says you can't reuse your insulation. ...
  • Find a Recycler. Generally speaking, you can recycle insulation. ...
  • Rent a Dumpster. Renting a dumpster is the quickest and most efficient way to get rid of insulation.

Can you reuse old blown-in insulation?

While it varies by type, blown-in cellulose is a type of insulation that can typically be recycled. The blower tool deploys the material to fill wall cavities, making it ideal for hard-to-reach spaces and poorly insulated areas in attics or crawl spaces.

How much to remove old insulation from an attic?

The average attic insulation removal cost is $900, but often ranges between $600 and $1,200, depending on attic size and whether your pro has to work with hazardous materials.

What should you not do when installing insulation?

Leaving Too Many Gaps

One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.

Is it worth removing old 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.

How long does it take to remove blown-in insulation from attic?

How Long Does Attic Insulation Removal Take? For a 1,500-square-foot attic, professional removal of blown-in insulation without hazardous complications can take as little as 4 to 6 hours to complete.

Can I use a shop vac to remove insulation?

It's going to get everywhere and make an even bigger mess, so you will need to get a vacuum to remove insulation from the attic. We use a 1,500-horsepower shop vac when we do the removal, and in most cases, hook that to a second attic insulation removal vacuum to get the suction we need.

Can you put too much blown insulation in your attic?

Mold and Mildew Growth

Having too much insulation in your attic can allow for the accumulation of moisture. This leads to mold and mildew growth, which can be extremely bad for your health.

Do you have to remove old cellulose insulation?

If there is a layer of fiberglass or cellulose insulation on the attic floor, as the air from your living space heats up and rises, it will want to move into your attic. You want to let that air get into that space without the hindrance of the old insulation.

What is the best insulation for attics?

Fiberglass Batt and Roll Insulation

Fiberglass batt and roll insulation is a common and budget-friendly option. This insulation comes in pre-cut batts or long rolls, making it easy to fit between the framing members, like joists and trusses, in your attic.

How often should you replace blown insulation?

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.

What time of year is insulation cheapest?

Best Time of Year to Buy Insulation

In this case, the spring is the best time, because you will also start to see savings in the summer months. The same is true for warmer climates, just different times of year because you'll want the job finished before the heat sets in.

What are the signs that indicate it's time to replace your home's insulation?

15 Signs it's time to update your insulation
  • YOU HAVE HIGH ENERGY BILLS. ...
  • YOUR AIR CONDITIONER IS CONTINUALLY RUNNING. ...
  • YOUR FURNACE RUNS CONSTANTLY DURING THE WINTER. ...
  • ROOMS IN YOUR HOME ARE EITHER TOO HOT OR TOO COLD. ...
  • DRAFTS COMING OUT FROM WALL SOCKETS. ...
  • THE WALLS OF YOUR HOME FEEL COLD TO THE TOUCH IN WINTER MONTHS.

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