Walls Insulation

Wall Insulation: Which R-Value Should I Choose?

R-value measures how well insulation resists heat flow — the higher the number, the better the thermal barrier. If you're building a new home, minimum R-values for your climate zone are set out in your energy report and required under the National Construction Code (NCC).

Beyond the NCC minimum, your ideal R-value also depends on:

• Wall construction — lightweight or timber-framed walls generally need a higher R-value than double-brick or concrete walls, which already have some natural thermal mass.
• Room use — bedrooms and living areas benefit from higher R-values to maintain a stable temperature and maximise energy savings, since they're occupied for longer stretches of the day.
• Climate zone — cooler regions like Melbourne and Canberra typically need R2.5–R2.7, while milder areas like Sydney are often well served by R1.5–R2.0.

Internal Walls vs External Walls

External walls form the building's thermal envelope and carry the greatest responsibility for keeping conditioned air in and outdoor temperature extremes out — this is where the bulk of your R-value investment should go.

Internal walls are more often chosen for acoustic performance than thermal resistance — separating bedrooms from living areas, or reducing noise transfer in multi-residential builds. Fletcher Soundbreak and Bradford SoundScreen are both purpose-built for this application.

Types of Wall Insulation We Stock

• Fletcher Pink Batts — Australia's most recognised glasswool batt, available R1.5 through R2.5HD, with the low-dust FirmaSoft formula for easier handling.
• Knauf Earthwool — made with ECOSE Technology and no added formaldehyde, a solid all-rounder for both thermal and acoustic wall performance.
• Bradford Gold Batts — Australian-made glasswool with strong thermal performance across a range of R-values, plus dedicated soundproofing options.
• Kingspan Air-Cell — a reflective foil insulation suited to slim wall cavities where thickness needs to be minimised.
• Foilboard — rigid reflective panels for wall applications where a thin, high-performance option is required.

How to Insulate Existing Walls

Retrofitting insulation into existing walls is more involved than new-build installation, since wall linings or cladding usually need to come off to fit batts correctly. Blown-in insulation is an alternative for some existing wall cavities that avoids removing plaster, though coverage and performance can be less predictable than a batt install.

For larger retrofit projects, professional installation is generally worthwhile — No Gap Insulation's installation team can advise on the right approach for your specific wall type.

Calculating Wall Insulation Coverage

1. Measure the total wall area to be insulated.
2. Subtract the area taken up by windows and doors.
3. Multiply by 0.9 to account for framing (studs typically take up around 10% of the total wall area).
4. Divide by the coverage per pack (listed on each product) to work out how many packs you need.

Why Buy Wall Insulation from No Gap?

No Gap Insulation has supplied and installed wall insulation across Victoria and New South Wales since 1998, stocking genuine products from Fletcher, Bradford, Knauf Earthwool, Kingspan and Foilboard with trade pricing and fast delivery available. Our team can help you work out the right R-value and product for your specific wall construction and climate zone.