SuperFOIL SF19+ Multifoil Insulation Review

SuperFOIL SF19+ is a high-spec multifoil insulation roll measuring 1.2m x 10m. Unlike standard mineral wool, it uses a multi-layer design to tackle heat loss through radiation, conduction, and convection. It is specifically marketed as a '3-in-1' solution, providing a radiant barrier and a vapour control layer alongside thermal resistance. Its relatively slim profile compared to traditional loft insulation makes it particularly useful for roof-line applications where space is at a premium, though it requires precise installation and specialized foil tape to reach its full efficiency potential.

In a UK domestic setting, SF19+ is best used to bolster existing insulation or as the primary barrier in conversions. Users generally report a noticeable reduction in rapid heat loss in upper rooms during winter. However, reaching the advertised R-values depends entirely on creating an airtight seal at every seam—a task that requires patience and a steady hand. If left with gaps or installed without the necessary air cavities on either side (as per manufacturer spec), the performance drop-off can be significant.

Realistic savings vary based on the current state of your home, but replacing an uninsulated roof space with SF19+ could reduce heat loss through the roof by up to 20-30%. For a typical UK detached house, this might translate to £150-£250 annually on heating bills at current price caps. However, if you already have 270mm of mineral wool, the additional savings will be marginal and take significantly longer to reach a 'payback' point.

Installation is physically demanding but manageable for a competent DIYer. The material is easier to handle than itchy glass wool, but you must factor in the cost of high-quality foil tape for all seams. Maintaining a consistent air gap is crucial for the foil to reflect heat effectively; sandwiching it flat between boards will reduce its rating.

There are no ongoing running costs. The true cost is the upfront price plus accessories like staples and foil tape (approx. £8 per roll). Expected lifespan exceeds 25 years if the vapour barrier remains uncompromised.