Before we get to the fun of choosing your wall surfaces, we need to make the important decision about choosing what type of insulation to use in your home.
Getting this right will mean you live comfortably year-round with a reduced carbon footprint – and a reduced power bill for heating and cooling!
In NSW you'll need to comply with BASIX (The Building Sustainability Index) regulations which dictates minimum 'R' (Resistance) rating for insulation. This forms part of their overall objective to ensure the environmental efficiency of residential dwellings to help meet state water and energy consumption targets.
Each insulation type comes with an UP-R value (the resistance to heat flow out of a building during WINTER), a DOWN-R value (resistance to heat flowing INTO a building during SUMMER) and a TOTAL-R value which factors in both qualities. Our Sydney climate with both hot summers and cold winters means that both the UP-R and DOWN-R ratings will be important for the energy efficiency of your home.
You’ll mainly be choosing between four types of insulation:
bulk INSULATION
Bulk insulation works by trapping heat inside millions of tiny air pockets within a thick material like polyester, fibreglass or wool. Bulk insulation is ideal for walls, beneath or between floors.
When choosing a bulk insulation material, we recommend a polyester filling. Although a little more expensive than wool or fibreglass, we prefer it as it is unaffected by moisture, has no breathable fibres and is therefore ideal for people with allergies. It is also comfortable to handle, where fibreglass based products can be irritating to the skin.
REFLECTIVE INSULATION
As the name suggests, this metal insulation made of aluminium or aluminized polyester and works by reflecting heat back where it came from. It's thin profile makes it great for pitched ceilings. It is great at reflecting heat away from a building in summer, but less efficient at keeping heat in a building during winter. In Sydney where we have both hot summers and cold winters, reflective insulation is best when combined in a composite with a bulk insulation filling to keep heat in a home.
COMPOSITE
Bulk insulation can be made even more effective by combining it with a reflective foil exterior to get the benefits of both products in one. These are ideal to provide extra protection in scenarios where thinner external surfaces are used (such as metal roof instead of tiles, or weatherboard cladding instead of brick). There are two main types of composite insulation:
Type one: Foil Blanket
This is a strong foil sheet backed with >55mm blanket insulation (various thicknesses available). This is laid between roofing batons and metal metal roofing sheets to provide thermal and accoustic protection. This compensates for the lack of density that roof tiles provide.
Type two: Rigid foil-backed foam
This type of composite is designed as a substitute for bulk insulation. It can be applied to the exterior of the frame - right beneath external cladding, or in internal walls, and between floors.
Spray
A new, incredibly effective (and of course, more expensive) solution with a higher R value than traditional insulation. Due to it’s more complex installation process and higher flammability, it must be installed by a professional.
summary
When choosing insulation, your builder will guide you through recommended products for each application in your home. Be sure to research the R-Value of any options provided, and consider your budget priorities and needs around sound and thermal insulation before making a final decision.