Sheffield Star online post #9, Insulation basics

Insulation is essential! I can’t say it any plainer than that. You wouldn’t step outside on a winter morning without your cardigan, that's a sweater for all you stateside readers, would you. So why leave your house to pour heat through the loft (attic), walls, windows, and floors?

The choice of insulation is important. Here are a few questions to consider when choosing insulation products.
• Is the insulation going to make you sick?
• Does your choice of insulation use too much energy to manufacture and require too many resources dug from the ground or pumped from oil wells to produce?
• Is the product recyclable or biodegradable?
• How effective is it?

Products like mineral wool and spun fibreglass consist of fibres that are easily inhaled. Much like asbestos fibres they can lodge in the lungs and may pose a health threat. These products also typically use a resin based binder to hold them together. Like most resins they are manufactured using petrochemicals and have a negative impact on indoor air quality. In some cases, like formaldehyde, these resins are known to cause cancer. These products are not generally recyclable and pose contamination risks at disposal. Because they rely on mining and industrial processes to manufacture they require more energy, embodied energy, to produce than more natural alternatives.

The manufactured or blown foam products also require massive inputs of chemicals and energy to produce. They are not recyclable and present similar if not worse disposal problems.
These concerns have to be balanced with the benefits of using some of these products. In some cases they are the best alternative, as in blown foam to seal and insulate cracks and gaps around pipes and wiring in walls or around windows. There are more natural alternatives however for almost all of the above mentioned products. For instance a blown foam product that is soy based has recently been developed.

For loft and under floor insulation, the more green options are natural fibres such as wool or hemp, and recycled cellulose or fabric fibres. Another option is cork, a product sustainably harvested from trees. Cork can also be used in cavity walls as it is waterproof as well. All these products are recyclable and have low embodied energy.

Effectiveness, measured in U-value, or R-value for those in the states, varies from product to product. For U value the number should be lower as it is a measurement of how much heat passes through the material whereas for R value the number should be high as it is a measure of who well the heat is blocked. Check it out before purchasing as a product that has half the effectiveness compared to another will require twice as much to achieve the same end.

I'll do another post where I’ll cover specific strategies for insulating your home.