We put a lot of thought into materials and what we consume. What’s in the food we consume? What’s in our skin care, our medicine? What’s in our cleaning materials? Ever stop and wonder, “What’s in my insulation?” Of course not. There’s a finite amount of time and energy in the day and – unless you work for an insulation company, it’s probably the furthest thing from your mind. But if you find yourself in the moment of ‘Oh, gosh, I need new insulation. What are my options? What will I be putting inside my home?’ Fear not. We’ve got you covered with a basic rundown of the materials used to make up your choices for insulation.


Let’s kick off with this pretty pink standard. If someone said insulation, the image of this fluffy pink stuff would most likely be the first to pop into your head. While it may look soft and fluffy, don’t touch it. It’s perfectly fine and safe for insulation, tucked carefully away in between your walls and ceiling. But these batts of pink clouds are made up of plastic that’s reinforced by tiny glass particles (or fibers). The combination is what gives this insulation its strength and insulation capabilities.


Hemp insulation is relatively new, and oh so fascinating. Usually made into block form, this natural material uses the stalk of the hemp plant for its base. The stalk is chopped into fine fibers and mixed with a lime binder and water. These three things come together to make a sort of concrete (or hempcrete) that is then formed into blocks, or laid out like actual concrete.


Another natural fiber filler, this might be the most eco-friendly insulation on the market. Between 75 and 85% of the insulation is made of of newspaper. Post-consumer waste newspaper. The last bit of this insulation – for very good reason – is a fire retardent. Considering it’s paper, combining it with flame suppressors such as boric acid or ammonium sulphate is vital. Otherwise, it and the rest of your house will go up in flames.  

Sheep’s Wool

Can you guess what natural fiber this insulation is made of? It’s not included in the name at all. Not one bit. Okay, jokes aside, this abundant and natural material is also finished by a separate agent for binding purposes. Around 5 or 10% of this insulation has a recycled polyester adhesive that holds it together in a usable form.

Spray Foam

Stepping quite a ways away from the natural material spectrum, spray foam insulation is just chemicals. Two types, to be exact. Often labeled like a vinyl (Side A, Side B) it’s a combo of isocyanates – the same material that makes paint, varnishes, and auto parts – the Side B component of polyol, flame retardant, and amine catalysts that create the flexible foam texture. While it isn’t the best choice if you’re going for non-toxic, if you have to install insulation into already existing walls, this is the type to use because installation is least invasive.