The Complete Denim Insulation Guide

What happens to your jeans once they’ve become too old? Instead of them being thrown away and going to landfill, manufacturers have found an eco-friendly way to reuse denim garments: denim insulation.

Denim insulation helps you save on energy bills by reducing the amount of heat that escapes the room. But how is it made and what are its pros and cons?

In this denim insulation guide, we dive into the specifics of this insulation type to help you make a well-informed decision.

Denim Insulation: How It’s Made

Denim insulation is made by recycling denim jeans scraps and clippings. 

First, the recycling facilities remove any accessories like zips, buttons, and the like.

Next, special machinery shreds the jeans and then transforms them into a loose-cotton form that looks a bit like candy floss. Afterwards, this material gets treated with boric acid to give it flame-retardant and insect-resistant qualities.

During processing, other materials join the mix, too, to enhance the thermal resistance of denim insulation rolls. Such substances include cotton and post-industrial denim. For that reason, you may stumble upon another name for denim insulation, which is cotton fibre insulation.

Advantages of Denim Insulation

Now, let’s dive into the plus points of denim insulation that make it stand out amongst other insulation types.

Incredibly Fire-Retardant and Mould Resistant

Because it’s treated with boric acid, denim insulation promises great fire resistance. It’s non-combustible since it’s Class A fire-rated. The flame spread rating is anywhere from 0 to 25.

In addition, homeowners can benefit from its resistance to mould, mildew, and pests that may easily find their way to the insulation.

Highly Sustainable

One of the coolest things about denim insulation is that it’s made of 85% to 100% recycled material. Even the manufacturing process itself uses up less energy than that of other insulation types.

Plus, when its lifetime is over, you can recycle your denim insulation once again!

Improved Indoor Acoustics

Another wonderful aspect of denim insulation is that it’s soundproof. Its sound absorption is higher than most other types of insulation, reaching up to 30% acoustic ratings.

This makes it a great option for reducing outside noise and trapping indoor sounds.

No Skin Irritation

Finally, denim insulation doesn’t contain itchy fibres like fibreglass. In other words, it won’t irritate your skin or eyes during installation, not to the same degree as fibreglass, at least.

Plus, it has a lower chance of causing respiratory issues, which is good news for people with asthma or allergies.

Disadvantages of Denim Insulation

Despite its many qualities, denim insulation has a few downsides you need to keep in mind before installing it in your house.

A Pricey Choice

Once you compare the price and installation of denim insulation to other insulation types, you’ll find that it can cost you triple! 

Here’s a table that sums up average insulation type prices:

Insulation materialAverage cost per m² (including installation)
DenimAround £50–60
Insulation boards£20–25
Rock wool£30
Spray foam insulation (PUR)£30 at least

So, for people on limited budgets, denim insulation may not be a suitable option.

Requires a Vapour Barrier

To prevent the denim insulation from getting wet and bending out of shape, it needs to go hand-in-hand with a vapour barrier. This is especially important in regions where the climate is always cold.

The addition of a vapour barrier means that overall costs will increase even more.


Where can you use denim insulation?

Because it’s available as batts as well as a loose-fill variety, denim insulation works for a wide range of applications all over the house:

  • Fitting between wall studs
  • Inside home studios and other settings where you need noise reduction
  • Installation between ceiling joists and rafters
  • Attics, cavity walls, and crawl spaces
  • Floor insulation
  • Solid walls

Which is better, denim or fibreglass insulation?

Both materials have their plus points and downsides, so deciding which is better is up to your judgement. 

Here’s a quick comparison to help you decide:

Comparison pointsDenimFibreglass
R-value3.52.9 to 3.2
Noise Reduction Coefficient1.150.9
Fire ratingClass-A ratingClass-A rating
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