When you do the math, you find roof surfaces represent 20-25 per cent of the built environment and act as “solar radiators” — so much so that around 93 per cent of a building’s heat gain can be attributed to radiant energy (meaning the sun’s rays converted to heat after absorption).
It makes sense then to employ a first line of defence that combats the specific heat source. That means reflecting the sun’s rays before they are absorbed and converted to heat. By contrast, insulation only treats the symptom of absorbed and stored heat.
Cool Roofs reflect maximum amounts of the sun’s light energy and light is reflected as light, NOT heat and hence the effect of reducing the build up and storage of heat in urban environments.
In Australia, most commercial buildings have zinc coated (Galv or Zincalume) roofing which act as poor reflectors of solar energy.
By reflecting more of the sun’s energy these surfaces can be 20-40°C cooler, translating into cooler occupancy zones, lowering cooling energy demand and thus delivering cost and energy emission savings.
optimise the Total Solar Reflection of a treated surface providing the opportunity to upgrade existing roof surfaces and create more sustainable structures. InfraCOOL Technology means surfaces reflect both the visible or “coloured” light and invisible infrared light which accounts for over 50 per cent of the sun’s total light energy.
Because InfraCOOL Technology maximises reflection of infrared radiation, even dark colours can be made cooler. InfraCOOL Charcoal, for example, can be up to 16°C cooler than conventionally formulated charcoal without changing the visual colour.
A cooler surface means less heat penetration, resulting in cooler occupancy zones and this means lower use of cooling energy — translating into energy cost savings and reduced associated greenhouse gas emissions.
Dulux AcraTex InfraCOOL technology can be applied to galv-zinc metal or concrete roof tiles in commercial or residential applications in protective membrane systems extending roof life cycle by 10+ years.
Dulux can also deliver InfraCOOL benefits throughout its range of AcraTex elastomeric wall coatings, reducing heat penetration into buildings and lessening the thermal stresses on concrete and lightweight facades.
To find out more about InfraCOOL Technology from Dulux visit our website.
1 20-40°C cooler surface example based on ASTM E1980 methodology and principles as published by the US EPA
20-40% cooling energy saving potential based on Cool Roof Case Studies by Lawrence Berkeley Heat Island Group using comparative (high solar reflectance) technology as defined by Dulux Cool Roof White verified TSR (Total Solar Reflectance) Data and Test Reports available on request