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Should I be thinking about R-values?

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With the winter creeping in I keep hearing and reading about R-values. What does this mean? And is it something I should be looking at?

The short story is that the R value of an insulation is its ability to resist heat flow. Commercially available insulation materials range in performance starting around 3.5 per inch for cellulose, to around 6.5 per inch for some high performance foams. They all have advantages and disadvantages, have a look at our insulation page to learn more about your options.

To give you a frame of reference, building code requires a minimum amount of insulation in homes, and those requirements vary regionally across the country, usually falling in the R 20-24 range.

And yes, you should be paying attention to it if you are involved in a building project, since builders often go with the lowest R values allowed by code. Perhaps this is to be able to offer you the lowest possible price in order to secure a contract or ensure maximum profits, but what this does is saddle you with much higher bills for the rest of your life in that home.

Personally, I would double code minimums at least, if for no other reason than to save money. To make an analogy, investing in insulation is like investing in a needle and thread to sew up a hole in your pocket so you stop losing your money.

What I would like to convey more than anything, is that if a builder tells you that building code requirements are enough and that added insulation is a waste of money, they are in a word, wrong. Building code minimums are just that, the bare minimum allowed. Building to those standards is like shooting for a D minus on an exam. It means you almost failed.

Ecohome has a program called Net Zero Heat, where building envelopes are designed specifically to individual climates so that little or no heat beyond the sun is required, and this can be achieved with approximately an additional 10 per cent investment on the total building cost. We don't advocate everyone aiming for that level, but we certainly would like to see the industry step it up a bit. So, take charge of your building project, and insulate!

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Meet our expert
Mike Reynolds

Mike Reynolds

Mike is a former home builder, a LEED for Homes Green Rater, and the editor of, a free online guide for healthy and sustainable building.