What Does R-Value Mean and How Much Do I Need?

R-Value measures the material’s resistance to heat transfer – a higher insulation R-Value means a greater resistance to heat transfer and this is an indication of how effective it will be at keeping homes at the desired temperature. It doesn’t matter what the brand is, or whether it’s traditional glass wool or foilboard, the R-rating is what matters. The higher the R-value, the more the material itself is able to prevent heat transfer.

Building a New Home?What is insulation R-value and how much do I need?

Australia is a large country with many different climate zones which means that the insulation requirements in each location can vary significantly. If you are building a new home then you need to check the insulation requirements on your energy report. Keep in mind that you can always upgrade to higher R-values than those specified.

What We Recommend as a Minimum

When customers ask us which R-value to install, we generally recommend a minimum of R2.0 wall insulation and R4.0 ceiling insulation. If your home has suspended floors then we also suggest that you install R2.0 underfloor insulation. These are the lowest R-values that we recommend installing.

The below table is intended as a guide for customers who are looking for a high quality finish.

WHAT R-VALUES TO INSTALL FOR GREAT RESULTS

Area of Home Main Purpose Recommended R-Value
Walls Thermal Protection R2.5 HD
Ceiling Thermal Protection R6.0
Underfloor Thermal Protection R2.0
Internal Walls Reduce Noise R2.0 HD
Home Theatre Rooms Reduce Noise R2.7 HD
Between Floors Thermal Protection R4.0
Between Floors Reduce Noise R2.5 HD

*HD means ‘high density’

Why Higher R-Values are Better

For the best results we recommend installing the highest R-value that you can afford. The rising cost of energy in Australia means that many home owners are opting for higher R-values such as R2.5 HD wall insulation for the external walls and R6.0 roof insulation. The higher the R-value, the better the thermal and acoustic performance of your home.

If you are looking to increase privacy within the home, then consider installing wall insulation in the internal walls. Installing R2.0 HD acoustic insulation (or higher) can help to create a quieter and more relaxing home. If you cannot afford insulation for all the internal walls, then simply choose the areas that you want to prioritise. For example, the walls around the toilets and main bedrooms.

To achieve the R-value written on the insulation pack it is important the batts or rolls are installed correctly. Even small 1cm gaps can reduce the effectiveness of your insulation. For more information check out our DIY install tips.

One Time Investment Leads to Savings Every Year

Installing a sufficient level of wall and ceiling insulation in any home and including wall wrapping in the insulation budget is one of the best investments home owners can make. It’s not uncommon for consumers to earn back the cost of the insulation through energy savings already in the first few years.

Value for Money – What is the Optimal R-Value?

When ordering bulk insulation, you will need to decide which R-value to go for. Generally, the higher the R-value, the thicker the material and the more effective it will be at resisting heat transfer. However, the higher the R-value, the higher the price. So, what most home owners naturally want to know is what is the lowest R-value I can invest in that will still prevent heat gains in summer and heat losses in winter?  The answer to this will vary depending on the climate zone of the residence.

Insulation for New HomesThe higher the R-value the better the thermal performance

The Building Code of Australia requires new homes to have an adequate level of insulation, where “adequate” actually depends on where you live along with a number of other factors. For someone living in a temperate climate, for example, a thin layer of insulation would keep the house comfortably warm in winter and comfortably cool in summer. But for someone living in a very cold climate, the same thin insulation would not be adequate. Find out what the required R-value is for your climate zone and consider upgrading to a higher rating for added comfort. R-value is the most important consideration when planning an insulation project and will guide subsequent decisions.

Higher Performance R-Value with Wall Wrap 

Every home owner should include foil wrapping around the frame of the house before the brickwork is started. This gives protection against the elements and will increase the performance R-value when used in combination with bulk insulation. Wrapping the frame of the house prevents the bulk insulation from coming into contact with the bricks and ensures that the necessary airgap between the timber and the bricks is maintained all the way around the house. The exact increase in performance may be somewhat difficult to measure, but it would be fairly safe to suggest that if a house was wrapped and fitted with R2.0 bulk insulation in the walls, the rating achieved would be closer to an R3.0.

  • Knauf Earthwool® Roof Batts

    $ 4.46$ 12.02 p/m2 inc. GST
  • Greenstuf® Polyester Ceiling Insulation

    $ 5.58$ 22.68 p/m2 inc. GST
  • Foilboard® Green Rigid Insulation Panels

    $ 7.38$ 33.00 p/m2 inc. GST