What is the ‘R Value’ in Insulation?

When it comes to building and renovating, you may hear your builder or trades refer to the ‘R value’ in your insulation materials. But what is this measurement and what does it actually represent? Let’s break it down.

What is the R value?

The R value is the measurement of an insulation material’s ability to resist heat transfer. Insulation R values generally start at R1 and go to R7 – the higher the value, the better the insulative properties of the material. Materials with higher insulation values on external walls work to both keep the heat in during winter and out during summer.

The purpose of the external walls and roof of a home are to protect the inside from the weather outside. This means the higher the R value of the materials used, the more even the temperature inside and therefore the more comfortable your home will be.

It’s important to remember that the insulation of your home is only as good as the weakest point. This means that a wall of roof with a really high R value will be pointless, without also having high value glazed windows and doors, which are the weakest points in a home.

Which materials have the highest R value?

When building, it’s important to use each material to its greatest advantage. Timber framed walls are generally a highly insulative material as they are layered with external cladding material, sisalation, insulation batts and internal linings. All of these layers add to the R value, which generally results in a rating of around R3.

A double brick wall has an R rating of R0.65, which means timber framed walls rate almost 5 times higher. Brick walls with insulation in the cavity have a higher R value, at approximately R2. Masonry walls have a different benefit, thermal mass used for storing heat, which works to the best advantage, inside the house.

What is thermal mass?

While insulation works to block heat transfer, thermal mass works to store heat energy within a material. For example, when brick walls are used inside the house, with a solar passive design, they collect heat from the sun, which is stored in the thermal mass. This means the house will warm throughout the day, and give the heat off during the night, keeping the home more even in temperature, without the same need of artificial heating. Conversely, during summer if bricks walls are shaded, they will absorb heat from inside of the house and give it off at night when the outside air cools.

The power of insulation is clear and demonstrates the importance of a passive home design – you need to have properly fitting windows and doors, in the right place to work in conjunction with the selected materials used in your home.

At Green Construct, we believe one of the best ways to achieve a highly insulated, passive home design is to build a reverse brick veneer home.

If you’re interested in learning more about having a comfortable home year round, get in touch with our team today!

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