What is R-Value and Why is it Important?

What is R-Value and Why is it Important?
November 8, 2017 Comments Off on What is R-Value and Why is it Important? Building Envelope Advent

Now that winter is here, a lot of people are suddenly noticing that their home is cooler than they like, or the furnace has to work very hard to maintain a comfortable temperature. If this is happening to you, we will need to look at the building envelope of your house.

There is one term, you are going to come across quite often: R-Value (or RSI – we will get into RSI later in this article)

What is R-Value?

What is R-value Insulation
R-value stands for resistance to heat. If an area offers no resistance to heat escaping from your house, it has an R-Value of “0”. If your wall would only have drywall on it, for example, it would have an R-Value of about R 0.5 meaning it has 0.5 times more R-Value than nothing. If your fibreglass insulation says it has an R-Value of R 22 it means that the insulation resists the heat exchange 22 times more than nothing.

Of course, a high R-Value in your walls and attic alone doesn’t keep your house warm. Factors like heat loss through gaps and the R-value of building elements like windows and doors play an important role.

More R-Value means more energy savings and lower cost Click To Tweet

Other than more comfort for your home, more R-Value also means more energy savings and less energy cost. The BC Building code sets minimum levels for how much R-Value a wall, roof or basement needs to have. The required R-Value varies from area to area.

As you can see in the chart below, a lot of the values depend on the thickness of the material. When we renovate houses that are 20 years or older, another factor comes into play. The walls of these houses are usually framed as 2x4” walls and don’t provide as much space for insulation as today’s 2x6” construction.

There are different materials we can use for insulation. You probably know the common fibreglass insulation, but the options range from the conventional batt insulation, rigid foam insulation to spray foam insulation. Each has pros and cons we will discuss with you when we meet to discuss your project.

Building Code Insulation R Value

You can download more detailed information about this section of the BC Building Code here: http://www.bccodes.ca/BCBC_9%2036%20EnergyEfficiency.pdf

When you look at the chart from the BC building code you will notice that the term “RSI” is used.

“R-Value is the imperial measurement and RSI is the metric equivalent. To convert RSI to R-value multiply by 5.67826; to convert R-value to RSI divide by 5.67826.”

R-Value Insulation

If you want to save more on your heating and cooling bill the insulation of your home needs to have a higher R-Value than this minimum. If you want to reach an insulation level for a LEED-certified or Net-0 home, you need to go even higher.

We hope you found this explanation helpful. If you have any more questions about the building envelope of your house, please contact us and stay tuned for more articles on this topic on our blog.

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