So… Just What Does R-value Really Mean?

Professor Plastics

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Most of us likely are familiar with the insulation term “R-value.” But I suspect many of us don’t know precisely what it means.

Why Insulation R-value is Important

This is an important topic. (And not just because Professor Plastics says so.) We use a lot of energy in our homes and buildings—approximately 40 percent of our nation’s energy—and much of that is used for heating and cooling our homes.

Unfortunately, much of this energy is wasted due to inefficient heating/cooling systems, outdated building practices, construction based on older building codes, wasteful personal habits, and (the big one) low-tech insulation. Wasted energy hurts our environment and hurts our wallets.

See? It is important.

So when we’re building a new home or upgrading an older one, choosing the right insulation can have a profound impact on our energy bills for the entire time we live there. Month after month after month…

What is Insulation R-value?

Quick quiz: what’s the “R” in R-value stand for? Reflect heat? Reverse air loss? Really good insulation?

Well, R means resistance to heat flow. The higher the R-value, the greater the insulating power. Home insulation manufacturers must conduct specific tests before they can make R-value claims—claims that are strictly regulated by the Federal Trade Commission.

But here’s the other critical thing: R-value is useful when choosing insulation, but it’s only part of the story.

How Insulation Works

Insulation does not work in a vacuum. It works within a system—your living, breathing house. It is applied between studs, under attic flooring, in basement walls, in roofs, etc. (R-value is determined in a lab, not your home.) So it’s also important that your contractor or your homebuilder chooses the insulation that works best in the real world: your house, based on its walls, its roofing, its windows, its climate, and more. This will help provide a better return on your insulation investment and improve the overall energy efficiency of your home.

So when you’re talking to your builder or contractor, discussing R-value is a good start. But follow up with a discussion about how and where the insulation will be used … because that could help save you even more money and energy over time.

And that is important.

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