Natural lighting innovation reduces cooling and lighting costs


The technologically advanced natural lighting HeatGuard range from Dimond is specifically designed to reduce transmitted heat inside a building while increasing visible light.


Used extensively on the Sylvia Park development in Auckland, HeatGuard 4 and HeatGuard 8 are two new natural lighting products which reduce the amount of heat transmitted into a building while still providing the highest level of visible light transmission.


An easy way to remember which product to select is the larger the number, the less heat that is transmitted.


Both products have infra-red ray reflecting additives in the gel coat that reduce heat without losing light transmission. Both also block 99% of harmful ultraviolet UVa and UVb rays for extra protection.


When this energy efficient product is used as roofing and cladding, costs for cooling and lighting in commercial and residential buildings are reduced.


How does it work?

The human eye sees visible light as the colours of the rainbow, with each colour having a different wavelength. The infra-red rays are within the thermal wavelength, and people experience this every day as heat. The heat felt from sunlight is the solar energy from the sun being transmitted by infra-red rays.



HeatGuard reflects most of the infra-red rays so they do not pass through the Durolite sheet, thereby reducing the amount of heat entering the building, without sacrificing the amount of visible light.


The ability of sheeting to differentiate between light and heat can be measured by dividing the total visible light transmission by the total solar transmission. This is called the Selectivity Index.


The chart below shows the difference in the Selectivity Index for the two grades of HeatGuard when compared to standard clear and opal sheet.



As seen in the chart, the Selectivity Index of HeatGuard is comparatively high. HeatGuard 4 selects and distinguishes infra-red rays, and is 28% more efficient in reducing heat while letting natural light in like a clear sheet, whereas HeatGuard 8 is 36% more efficient than any opal sheet.


Both products are part of the Durolite natural lighting range of roofing and cladding applications that can be used with Dimond’s metal roofing and cladding products.


Both come in a wide range of profiles and sheet lengths, and are also available in foot trafficable sheets.