cavity Wall insulation costs and prices

The costs of cavity wall insulation in existing homes vary with the type of wall, the insulation material and the conditions surrounding the installation.

Masonry-Brick homes

According to EnergyTrust.org, insulating the cavity walls of an existing gas-heated, semi-detached masonry/brick home with three bedrooms costs around $800 (£500). This unsubsidized installed cost, may be reduced with municipal or state incentives for energy-efficiency improvements*.

Without grants or tax incentives, the installed cost of cavity insulation in the case considered above ($700 /£500) can be recovered in around 4 years (for energy savings estimated at about $150-$180, £90-110£ per year, according to the same source).

* In the UK the Carbon Emissions Reduction Target (CERT) incentive amounts to about half of the value of the insulation cost. In USA, for information on state and municipal incentives, see: Database of USA State Incentives for Renewables and Efficiency.

Cavity wall insulation with loose fill materials

In USA, in typical wood-frame homes without low or no cavity wall insulation, the price of filling wall cavities with common loose-fill materials (fiberglass, cellulose and rock-wool insulation) may vary from $.50 to $1,5 per square foot - a wide variation that depends on elements like the cost of drilling the holes demanded by the insulation and/or the cost of repairing the walls after the insulation.

For larger houses and whenever accessing the wall cavities or drilling the holes (to inject the insulation material) is easy, prices will be closer to the lower limit.

In new homes the costs per square foot will also be lower.

Prices of wall cavity insulation with sprayed-on materials

Instead of loose-fill materials, wall cavities can be insulated using sprayed-on cellulose, fiberglass and mineral wool fiber. But this option will cost a little more (sprayed on materials are more expensive), with the final prices also depending largely on installation issues, type of home, etc. Average prices around $1 to $1.30 per square feet (to attain an R-19 value) are common.

These prices are at least 50% higher than the average and traditional batt insulation.

Sprayed on foams Prices

Sprayed-on foams is another possible alternative in wall cavity insulation of existing homes, with obvious advantages in terms of energy-efficiency. Sprayed-on foam insulation can fill and seal miniscule cracks and seams in walls, providing superior energy-efficiency.

The problem with sprayed-foam insulation is that it a bit more expensive. Prices may reach $2 per square foot for each inch of thickness...

Elements that make the cavity wall insulation cheaper or more expensive

As said before, cavity wall insulation prices are strongly affected by the type of walls and the type of works associated or demanded by the cavity insulation (drilling of holes....), etc.

Installing the insulation in renovations involving painting or during re-siding will strongly reduce the prices of cavity wall insulation.

See:
Types of Cavity Wall Insulation
Problems with Cavity Wall Insulation