Green methods to insulate your school

Staying on top of school facility budgets can be tricky, especially when it comes to invasive maintenance procedures like installing insulation. But insulating a building doesn’t just have the benefit of keeping the interior warmer in cold weather and cooler in hot weather, it also significantly reduces energy expenses and, in the long run, can pay for itself. In a large building or campus such as a school or university, anything that can reduce energy bills should be considered, but what shouldn’t be forgotten is the environmental impact of insulation. Most traditional methods of insulation leave large carbon footprints and can even cause health concerns, so how can schools become more eco-friendly with their insulation while also saving on energy bills?

It’s estimated that non-insulated buildings lose up to 40% of their heating through the roof alone. There are several kinds of green insulation types to prevent this heat loss, each with their own cost and efficiency advantages and disadvantages.

Spray on foam

For large buildings or campuses, spray foam insulation is effective and non-disruptive thanks to its relative ease of installation. It can be applied to most areas – even those that are difficult to reach – and even helps to soundproof walls. This makes it ideal for both roof and wall insulation.

This spray foam insulation is known as Icynene, made from castor oil. When sprayed, it has the consistency of paint, but upon hitting a surface it expands to nearly 100 times its volume, trapping air in small bubbles during the foaming process. It allows water vapour to escape, preventing moulding. It sounds great, but it’s not all good news, sadly. Most importantly, it tends to be expensive, and it can be hard to justify the high costs based on environmental benefits and convenience alone. There’s also the chance that, because the foam insulates so tightly, ventilation systems will need to be installed. If things get particularly cold in your area, then you might need to invest in a heat recovery unit to warm the incoming air.

Cotton insulation

Cotton has a lot in common with fibreglass insulation: it insulates with the same efficiency and can be rolled into batts. The big difference is that, unlike fibreglass, cotton does not contain formaldehyde, linked to some forms of cancer. You can also rely on cotton to not cause respiratory problems. In addition, the material absorbs moisture well, is an insect repellent, and is flame retardant if treated with boric acid.

Environmentally speaking, cotton is essentially recycled materials and scrap from clothing manufacturers. Cotton plants are both natural and renewable, making it one of the most environmentally friendly methods of insulation on the planet. The bad news, however, is that it costs around double the price of fibreglass, which is a lot considering the energy savings will be similar.


Aerogel is a fascinating substance: it’s the lightest, least dense solid substance known to man. It also provides the best insulation per square inch possible. The substance was originally developed by Samuel Stephens Kistler in 1931, apparently on a bet. He had wagered with a friend that he could remove the liquid from a jam jar without causing the contents to shrink. He did this by removing the liquid and replacing it with air. This is essentially how aerogel is developed today; scientists remove the liquid from silica under high temperature and pressure, leaving a material that’s more than 90% air. Its molecular structure makes it very difficult for heat to travel through.

Aerogel is thin and four times more efficient than fibreglass or foam. Thanks to its flexibility and thinness, it can be used in curved walls and tight spaces, and can save several meters of space compared to other insulations methods. There are also the benefits of being much greener and healthier than materials like fibreglass. However, the bad news is that aerogels are, perhaps expectedly, very expensive. NASA use them to insulate their rockets, and aside from them, very few companies in the world even produce aerogel. If your campus is particularly large, then it could be difficult to justify using this insulation technique throughout all the buildings.

Polystyrene Insulation

Since it’s a plastic, polystyrene has a negative reputation for being environmentally unfriendly. However, it can be used to insulate your buildings with a very high level of efficiency and is even recyclable. Polystyrene insulation comes in several forms, including rigid boards for installation in rooves and even foundations (they also add to the structural integrity of walls). For more flexible installation, however, there is also a spray foam option.

Polystyrene is quick and simple to install thanks to the foam and easy-to-cut-into-shape boards, which comes in particularly handy when trying to insulate irregular-shaped buildings. It’s also relatively inexpensive, making it the most affordable option on this list. However, there are certain aspects that you would need to consider. Firstly, it’s important to be aware that despite the efficiency of this method of insulation, polystyrene insulation still isn’t as insulating as fibreglass. It’s also water resistant, which sounds like a good thing but will actually allow moisture to build up within walls.

Perhaps the most important factor to consider is that polystyrene foam is incompatible with electrical wiring. The foam will erode the covering on electrical wires, and schools tend to have a lot of wiring, making this a potential dealbreaker. It’s possible for companies to cover the wires with a resistant coat to protect them, but this would be an additional, costly service.

No matter what insulation method you settle on, there are several questions you need to ask your provider. Are their materials generated from environmentally-friendly sources? Are those materials capable of keeping out damp? What is the life expectancy of the insulation? If the insulation needs to be reinstalled in just a few years, then the energy bill savings become redundant.

Staying green and insulated can be an expensive goal for a school, but when you consider the savings for both energy bills and the environment, coupled with the reduced health risk, you could argue that the investment will pay for itself, in more ways than one.

05 Mar 2018

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