CHOOSING INSULATION

There was a time when insulating a home was just a matter of rolling some glass fibre quilt in between the ceiling joist and making sure you kept a good draught flowing through the loft. Then someone discovered a hole in the ozone layer and things started to get a bit more complicated. Around this time the British also discovered, in a blind glimpse of the obvious, that you can live in your loft. Up until that moment most homeowners thought that some ancient law decreed that a third of our potential living space needed to be reserved for storing Christmas decorations, suitcases, a broken guitar and a noisy cold water tank.

The coincidence of these two unrelated events meant that the building industry not only had to come up with better insulation products, they also had less space to put it in. They rose to the challenge magnificently. The choice of insulation materials and methods is now vast and somewhat confusing. The truth is out there but how do you know when you see it, with manufacturers making claims and counterclaims and even taking some hefty side swipes at each other.

MULTIFOILS

A good example of the fog now surrounding insulation is the introduction of reflective multifoils. This spin-off from space exploration seemed to overcome the problem of increasing thermal performance without increasing the dimensions of walls and roof timbers. It seemed too good to be true and there are those who believe it is. The figures were immediately challenged, not surprisingly by the manufacturers of more conventional insulation. It might work on the moon they suggested but the tried and tested hotbox method of measuring insulation seemed to suggest that there was no place for it on this planet. Multifoil manufacturers, who have now formed an association, claim that as a greater amount of heat is lost through radiation than conduction or convection, reflective foils are a better way of preventing that heat loss. So far they have been unable to come up with a satisfactory way of proving this claim but they are working on it but we will update this if we get any news to the contrary.

To be fair to both sides of the battle lines, if heat travels in different ways (radiation, air movement and conduction) then it would seem obvious that we need insulation that counters all these effects. The most likely winners will be manufacturers who have a foot in both camps and combine various technologies to produce hybrid products which resist the passage of all heat not just some of it.