Passive cooling techniques and technologies is one way of keeping cool during the summer season. It is, after all, the least expensive means of cooling a home and with the lowest environmental impact.

However, reflective insulation is also another method for keeping homes cooler in summer as it deflects radiant heat from its polished surfaces. Also known as reflective foil laminates or RFL, this type of insulation usually comes in thin sheets of aluminium foil laminate onto paper or plastic, available in sheets or batts form.

There are currently four types of reflective insulation available:
  1. Reflective foil laminate
  2. Multi-cell reflective foil
  3. Expandable concertina-style foil
  4. Foil bonded to bulk insulation

Supplied in rolls, reflective foil laminate is foil laminated to paper with glass fibre reinforcement. It is used mainly as roof sarking and wall insulation.

Multi-cell reflective foil is usually two, three or four layers of laminated foil installed over ceiling joists, between or across wall studs.

The double-sided expandable concertina-style foil is used mainly under timber floors and between wall studs. It has an adjustable width to suit varying gaps.

Finally, the foil bonded to bulk insulation is a reflective foil bonded to batts, blankets or polystyrene boards. Blankets usually insulate cathedral ceilings and under flat roofs.

According to Your Home, the total R-values for reflective insulation are supplied as up and down values. The total values depend on where and how the reflective insulation is installed.

R-value is a thermal performance rating system that aims to help builders and insulators alike determine the right insulation product for their area and building project. Simply put, the higher the product’s R-value, the greater the insulating effect. If two products hold the same R-value their insulation performance would be the same, regardless of their manufacturing difference. (Read more on R-values here.)

Fletcher Insulation 's Sisalation® Heavy duty (453) anti-glare reflective foil laminate is used for sarking and insulating under metal roofs for residential, commercial and industrial buildings.

Similarly, the SisalSHED™ reflective foil laminate is used in the sarking of shed and garage roofs and walls and provides an effective barrier against moisture, vapours, wind, heat and dust penetration when overlapped.

The InsulBubble™ reflective insulation consists of a layer of polypropylene weave to foil and a layer of PE film to foil both laminated to a fire retardant cell structure. It can be used in a variety of residential and commercial applications to increase the thermal performance of the building and to act as a vapour barrier.

The AIR-CELL Thermo reflective Flexible Insulation from Kingspan Insulation provides the perfect solution for floors, roofs and walls. A fibre-free insulation, it incorporates advanced thermal properties that help achieve 6-Star house energy ratings.

According to Kingspan, AIR-CELL will reflect up to 97% of radiant heat away from its surface. The heat that is absorbed from the insulation is further reduced by the resistance of the polymer air cell structure, keeping you warm in winter and cooler in summer.

According to Sustainability Victoria, adequate performance can be achieved by combining reflective insulation with bulk insulation and/or using specialist foil products, provided they are carefully and properly  installed.