Insulation Articles
What is an R-value?
An R-value is a term that might come up when you are researching insulation and it can be very difficult to work out exactly what it means and how it might relate to your house!
What is an R-Value?
In simple terms an R-value is a measure of how thermally resistant a material is - the higher the value the better it is at insulating your home. Every material has an R-value, for example glass has a very low R-value (that's why you can feel the cold penetrating through the glass in the winter! On the other hand, polystyrene has a relatively high R-value - hence its use in coffee cups to prevent you from burning your hand.
How does an R-value relate to my home?
The ceiling, walls, windows and floor of your home will all have different R-values depending on the materials they are constructed from and the levels of thermal insulation installed. Low R-values will leave your home vulnerable to heat loss in winter or heat gain in summer, which will be contributing significantly to the cost of heating and cooling your home and making your home less comfortable to live in.
How do you work out the total R-value of my home?
To work out the total R-value you of your walls you would simply add the values of every component that makes up that wall. If you have an uninsulated brick veneer house, your wall will probably have 13mm of plaster board with an R-value of around 0.07, an air-gap of around 100mm, which also has an R-value of around 0.14, and of course, a single brick with an r-value of 0.05. The total R-value for this wall then is 0.26. So it is easy to see that the addition of wall insulation of around 1.5 will make a significant difference to the overall insulative properties of this wall.
What R-value should I use for the insulation in my home?
Unfortunately one R-value doesn't fit all. Depending on where you live there are different R-value (and insulation-type) requirements to suit your climate. As a general rule, the colder your climate - you'll be better using bulk insulation (such as insulation batts) and the higher the R-value, the better. In warmer climates, you might use reflective insulation with a high r-value and possibly a combination of the two types.
What is an up/down/winter/summer R-value?
Some types of insulation have different R-values depending on which direction the heat is travelling. This is usually the case with reflective insulation only. Bulk insulation, or insulation batts do not have this aspect. The up/winter R-value is the insulating value for when the heat is trying to escape your home, the down/summer value is for when you are trying to prevent heat gain, usually during summer. Reflective-type insulation is usually more effective in the down/summer direction, for this reason it is used in hot climates to prevent overheating.