Keep your cool
Ever thought a house or building would look great painted in a sleek, dark colour – then had to shelve plans for fear of the heat damaging the substrate or the building getting unbearably hot in summer?
Well, forget all that. Resene Cool Colour technology makes painting exterior surfaces in dark colours both easier and safer. It can be used on all sorts of exterior materials and applications, from weatherboards and concrete to windowsills.
A Resene Cool Colour looks the same as normal, but reflects much more heat – so it doesn’t get as hot as a standard paint would. The pigment technology allows the coating to retain its usual visible shade, but gives heat back from the surface, reducing stress on the coating and substrate, and limiting subsequent heat related damage. The technology also minimises the buildup of unwanted heat in the building, keeping air conditioning and cooling costs down.
In terms of technology, the Resene Cool Colour effect can also be seen in plants. Most plants have leaves of a very high chroma green. If those leaves reached the same temperature when exposed to solar radiation as those of a similarly coloured paint they would shrivel and die. The fact they don’t is because that pigment - chlorophyll - absorbs what it needs from the visible range to photosynthesise but reflects the infra-red range, keeping the plant cool.
When it comes to roofs, having a darker shade in winter will not make much difference to how hot your roof – and home or building will get – as when it is cold they will be cold too, however in summer it will make a difference as to how hot your home or building will get by reflecting the heat away from the building.
Resene Cool Colours are available in an extensive colour range tinted into a wide range of Resene Environmental Choice approved paints and stains, including Resene Lumbersider waterborne satin, Resene Sonyx 101 waterborne semi-gloss, Resene Hi-Glo waterborne gloss, Resene Enamacryl gloss waterborne enamel, Resene X-200 acrylic waterproofing membrane, Resene Lustacryl semi-gloss waterborne enamel, Resene AquaShield mineral effects and Resene Waterborne Woodsman wood stain. Available exclusively from Resene.
Although it may be hard to believe, these two colours behave the same in test procedures. The test procedure involves fixing thermocouples onto the backs of these panels (ensuring a good thermal contact); shining an infra-red light onto the painted side of the panels and plotting the temperature rise of the panels on the thermocouples. The grey panel is a standard coating. The black panel uses Resene Cool Colour pigments. The black Resene Cool Colour panel has the same infra-red (heat) absorption as the standard paint finish on the grey panel, demonstrating the reflective benefits of Resene Cool Colour technology.
See the Resene website for more information:
www.resene.co.nz/comn/whtsnew/cool_colours.htm
Way Cool
Graphs
Adidas Building
Annabel M. 95°
Vincent Heeringa 282°
A great project.
In Feb 2007 we painted our dark green colour steel roof areas on our home and office with Resene Hi Glo pearl lustre. The reduction in roof space temperature avoided us having to install air conditioning in several spaces throughout the building - a great saving in energy costs.