Man measures R-value of house

What is an R-value and how does this relate to insulation?

Measuring Thermal R-Value

You’ve probably heard the term R-Value before, but what is this and what does it mean? In this article we discuss Insulation R-Values and New Zealand’s new R-value requirements for new builds and existing homes.

Firstly, let’s look at what an R-value is.

An R-value is a unit of measure for the thermal resistance of a product or material. R Values are used to measure the thermal resistance of windows, doors, walls and insulation. If you look specifically at home insulation, its R-value tells us how effective that product is at stopping heat transfer from the outside to inside (or vice versa).

If insulation has a high R-Value (a larger number), this means that the insulation product is more effective at slowing the rate of heat transfer. On the other hand, if the R-value is low, it means that the insulation products or materials are not as effective, at heat transfer will happen more quickly.

Let’s look at an example.

You’re living in an older New Zealand house with a fireplace as your main source of heat. When you light the fire, the house warms up. If your home contains insulation with a high R-value, the house is likely to stay toasty warm for quite a while after the fire is put out. If your home has poor insulation with low R-values, the house is likely to rapidly cool off once the fire is extinguished.

High Insulation R-Values keeps your home warm

Homes containing high performance insulation retain their heat for longer. This makes them more energy efficient and reduces the amount of effort you need to put into heating and cooling your home.

Ok, so that makes sense but how does insulation R-values affect me?

If you’re living in a home where you don’t giving heating or cooling a second thought, you’re probably living in a newer, well insulated house. If you struggle to keep your house warm and are having to run heaters constantly to maintain a temperature, then this is probably more relevant to you. Dampness and condensation are other obvious signs of a poorly insulated house.

Insulation standards for older New Zealand homes are typically very poor. Even until recently, the insulation standards in most homes have been much lower than most other countries. In recent years however the Government has developed programs to help fund the upgrade of insulation in older homes. They have also recently increased the insulation standards for all newer homes. You can read about the new insulation standards in our article about the changes to H1 Energy Efficiency.

In summary, all new homes built in New Zealand insulation with good thermal resistance values. This means a minimum of R6.6 in the roof and R2.0 in the walls. It’s great to see these standards improve and well insulated homes will keep as warm, dry and healthy.

How do you work out the insulation R-values in your home?

If your home has been built recently, the Insulation R-values should be noted on your plans. If you’re living in an older New Zealand home, this is a little bit more difficult to work out. Many older homes lack wall insulation or have poor ceiling insulation.

The best thing you can do is give us a call and arrange for a free insulation assessment. Our assessor will look at your current insulation and provide a summary of any improvements that could be made. Contact us today to arrange your free home assessment.