- Hristiyan A. C.
Which Types of Insulation are the Most Environmentally Friendly?
Updated: Nov 2, 2022
A remarkable and convenient development in our modern world – thermal insulation provides us with the best means of maintaining temperatures in our homes, while also saving us household costs in the process. Your home's insulation can either reduce the inside temperature during the blazing summer spells or act as a means of retaining the heat within the rooms for colder seasons. There’s also that teeny little bonus in that it makes your home all the more comfortable!
No matter what, your humble little abode should have adequate insulation to keep you and your loved ones comfortable, right? Well, while it is totally understandable to desire the utmost conditions for comfortable living, we sometimes have to make sacrifices for the greater good – in this context, we’re alluding to the big blue rock we live on!

Yes, environmental awareness is everywhere these days, and for good reason. Harmful emissions are a number one concern for a large majority of people, but not everyone knows where to start with their “going green” plan. For one, the right answers come after the right questions – and knowing what these ‘right’ questions are!
In the case of thermal insulation, your first step would be to consider the various eco-friendly options and their respective pros and cons.
Cellulose
What can be more environmentally friendly than an organic compound? Rhetorical questions aside, cellulose has proven to be one of the most tried and true materials for balancing your insulation and environmental needs.
Of course, cellulose is often a blend of recycled wood fiber, paper, or even plant substances like corn cobs. This type of insulation provides an R-value similar to that of fiberglass, which is another somewhat eco-friendly option (although to a much lesser degree).

Cellulose is ‘blown’ into crevices and cavities, meaning that the pieces are meant to settle and fit around various curvatures, bends, and other asymmetries within the walls. In some ways, it is comparable to spray foam, but with the obvious advantages that come with being a dry substance.
From a sheer production point of view, cellulose is also the most energy-optimal, as its recyclable nature barely produces any pollutive byproducts, and requires minimal physical or chemical resources during the conversion process.
Overall, you sacrifice the least when it comes to choosing this type of insulation. The only downsides to using it are its proneness to sagging or absorbing moisture, and the amount of dust generated when installing it.
Cotton and Denim
This variety of insulative material is mostly salvaged from old clothing, thus having the reprocessed aspect of cellulose in common. In a similar vein, it requires little expenditure of energy resources, whilst also producing minimal or no chemical byproducts.
Also just like cellulose is its fire retardant treatment – using boron-based inhibitors, this type of insulation becomes fire-resistant in addition to being mold/fungi and pest-resistant. Other neat bonuses include its soundproofing quality and resistance to windier weather.

The downsides compared to the more popular cellulose variety come in the form of rarity and malleability (or lack thereof). Being harder to come by means it’s expensive, and the lack of malleability can often be the last straw for some people looking to apply easily adjustable and moldable material for their specific needs. It’s a good idea to evaluate your decision based on availability and whether your walls are truly meant for this option. Consulting with a professional is a must in this case.
Nevertheless, denim or cotton blends for insulation can be a good choice for those who can afford it, and are looking for an alternative that provides better respiration and less dust byproduct.
Cork
Cork is impermeable and quite versatile. During the steam-heating process, this bark byproduct expands and becomes a semi-rigid board. There’s quite a bit of diversity when it comes to density – ranging from one-inch to thirteen-inch boards in terms of commercial availability. Its overall thermal performance is consistent too, unlike polyiso options.

When it boils down to just how ‘green’ it is – this insulation type requires only two things, cork, and water, so we’ll let you be the judge. Being made of organic substances, it won’t release harmful chemicals when decomposing either, so there’s that aspect to cross off the list.
Cork is best for larger installations, rather than smaller homes. It’s also considerably harder to come by in North America, unlike in Europe for example.
Other benefits come in the form of its hypoallergenic, anti-microbial, and anti-fungal/mold qualities.
Honorable Mentions
Some less obvious alternatives are icynene and aerogel. Both of these options offer structural integrity and top-notch heat insulation. They might not seem like eco-friendly variants at first, but their reduction in energy bills helps them in being ‘green’ in statistical terms, as they lower energy expenditure by a decent sum. However, they only serve as honorable mentions due to the chemical byproducts involved in the production of plastic and spray foams/gels.
All in all, your choice will depend on the locale, availability, and cost. Either way, you’re bound to find something that balances both eco-friendliness and utility, so long as you avoid polystyrene.