What R-Value is best for your home?
The Building Code of Australia (BCA) has outlined energy efficiency provisions for new homes which include the inclusion of insulation in ceilings, walls and some floors. The value of insulation required to meet the deemed-to-satisfy provisions for energy efficiency are intended to be seen as a minimum standard – not best practice.
Step 1. Determine your climate zone from the map below.
Climate zones affect the levels and type of insulation. The purpose of the insulation, whether it be to keep the heat in or out (or both) will affect the R-Value required. As a general rule, climates that need to keep the heat in, require higher R-Values.
Step 2. Determine the minimum R-Value of insulation needed to meet BCA deemed-to-satisfy requirements in your climate zone.
The values in this table can also be used as a guide when installing insulation into alterations and additions, or retrofitting existing homes with no insulation.
It should be noted that these are minimum values only, and that upgrading your insulation to a higher material R-Value can provide a better level of the resistance to heat in your home. Understanding the difference between R-Values is important as it can mean the difference between getting an average product for your home with average benefits, and getting the best product for your home.
Minimum R-Value Of Insulation Needed To Meet BCA Deemed-To-Satisfy Requirements
| Climate Zone | Zone 1 & 2 (<300m) | Zone 2 (>300m), 3, 4, 5, 6, 7 | Zone 8 |
|---|---|---|---|
|
90mm studs, brick veneer with Enviroseal |
R2.5 |
R2.5 |
R2.5 |
|
90mm studs, lightweight cladding with Enviroseal* |
R2.7 |
R2.7 |
** |
*If metal framing is used, a thermal break tape must be used over the Enviroseal fabric.
**Contact Bradford for a solution.
Note that the use of high levels of insulation to meet energy efficiency and comfort requirements can lead to an increased incidence of condensation in walls and attic spaces in cold climates. This is because of the insulation’s effectiveness at keeping the warmth within the home but vapour’s ability to pass through plasterboard and standard insulation. To address potential condensation problems Bradford recommends the installation of Anticon roofing blanket under metal roofs where the ceiling is insulated. The inclusion of building membranes with a high permeability, such as Enviroseal, and the inclusions of roof ventilators will also help minimise the incidence of condensation. Contact Bradford Technical personnel for detailed information.
