Why Wall Insulation Matters

Walls are the second largest source of heat loss and gain after the roof. Without insulation, your HVAC systems work harder, raising bills. Wall insulation stabilises indoor temperatures, reduces noise, and boosts your home’s energy star rating. Older homes (pre-1990s) often lack wall insulation, making retrofitting a wise upgrade that pays off in 3–5 years.

Types of Wall Insulation

Different wall construction methods require different insulation approaches.

• Batt or Blanket Insulation: Pre-cut glasswool, rockwool, or polyester batts. Great for stud walls in new builds.
• Blown-in Insulation: Loose-fill materials like cellulose or glasswool, injected into wall cavities—ideal for retrofits.
• Rigid Board Insulation: Foam boards offering high R-values in thin layers, useful where space is tight.
• Reflective Foil: Installed behind cladding, excellent for reducing radiant heat in hot climates.

Internal vs External Wall Insulation

Insulation can be placed internally or externally depending on the construction type.

• Internal Walls: Improve zoning, comfort, and acoustic privacy (bedrooms, home offices).
• External Walls: Installed between studs during construction or via cavity fill/recladding for retrofits.

How Wall Insulation Improves Comfort

Beyond energy efficiency, wall insulation enhances liveability.

• Temperature Regulation: Stays cooler in summer and warmer in winter.
• Energy Efficiency: Cuts HVAC demand by 20–40%.
• Noise Reduction: Blocks traffic, neighbour, and rain noise.
• Moisture Control: Vapour barriers prevent condensation, mould, and damp.

DIY or Professional Installation?

Wall insulation is trickier than ceiling or underfloor insulation. Professionals use specialised tools to ensure even coverage. DIY is possible during renovations, but not recommended for retrofits due to safety and coverage risks.

Costs and Savings

Wall insulation costs vary depending on method and material.

• Batts: $40–$60 per m² installed
• Blown-in insulation: $35–$55 per m²
• Rigid foam boards: $50–$80 per m²

Signs Your Walls Need Insulation

• Rooms heat up quickly in summer and get freezing in winter.
• Energy bills remain high despite efficient appliances.
• Cold drafts near walls or uneven room temperatures.
• Excessive outside noise entering the home.

Final Thought

Wall insulation is one of the smartest upgrades for any home. Whether building, renovating, or retrofitting, the right solution enhances comfort, lowers costs, and supports sustainability. Professional guidance ensures you get lasting results.