Insulation gives protection from heat gain in summer and heat loss in winter. The performance level of insulation is measured by a term called the R-value. Essentially it is a rating which is calculated by measuring the performance of the insulation in both summer and winter and then finding the average between the two extremes.
As an average, the R-value rating can be very misleading. For a true performance rating evaluation, the summer and winter values need to be considered individually (not united as a single average). Typically, reflective (silver foil) has a high summer R-value and a lower Winter value. Conversely bulk (loose) insulation has a higher Winter R-value than summer value. The best insulation system is a combination of performance reflective and bulk insulation.
The importance of sealing the outer building foil system is significant. Any breaks, leaks or thermal bridges drastically reduce the insulative performance. In Europe there is a great emphasis on hermetically sealing (air tight) the outer shell of the building to provide a superior insulation system.
The insulation types featured here are in our opinion the best performing and have sustainable features inherent to their manufacture.
SUMMER INSULATION
Reflective high performance products that provide a superior Summer performance - minimising the need for cooling.
For a great reflective insulation product, Urban Green Living recommends Retrosheild and Glareshield. It was short listed in the Australian Design awards in 2001. Consisting of a twin sided aluminium mesh wrapped polyethylene "bubble pack" 7mm thick, reflecting up to 97% radiant heat. Can be used over rafters, under battens on tiled roof, over or under batten on domestic metal roof, ceilings and walls.
Equivalent R values see manufacturer's technical literature for details. Visit website.Download Glareshield.pdf
Another great reflective insulation product are Silver Batts: a winner of an Australian Design award.
This product consists of multi layer aluminium foil sheets with air pockets, reflecting up to 100% radiant heat. Double layer and triple layer formats are for ceilings and floors, pleated format is for walls and floors. Made of double-sided aluminium foil, 7 micron thick, bonded to unbleached recycled Kraft paper. As a result, this product has a very low embodied energy when compared to other insulation products.
Equivalent R values: Summer Winter Average Double layer 4.0 1.5 2.8 Triple layer 6.0 2.5 4.3 Download data sheet for more info:
WINTER INSULATION
Bulk insulation . These products are best for winter performance - the higher the R-value, the less heating you need. Urban Green Living recommends products that are made from recycled or sustainable sources, including:
Polyester batts, which can contain recycled product, are safe to work with (contain no harmful pesticides and flame retardants) and can be fully recycled.
Wool batts are another option which have excellent insulating properties and are safe to work with. They contain some pesticides to protect against moth attack but are not harmful to humans.