We're building a veranda/pergola on the north facing wall of our house in Melbourne. Also installing double glazed windows with low-e glass in same wall.
The veranda/pergola has 900 mm of cladding against the house to protect the wall from weather and to act as an eave. I am considering using Laserlite 3000 above the windows to ensure more light transmission but can't work out whether this will let more heat in than Colorbond. With double glazing and low-e to trap heat in winter, we don't want to do the same in summer!
The available data which doesn't seem comparable is:
Laserlite 3000 'Ice', light transmission 47%, shading coefficient ration .37, SHGC .32
Colorbond 'Classic Cream' or 'Surf mist', solar absorptance .32
As the Laserlite will protect the windows from direct sunlight, I think that any heat it lets through will be mainly long wavelengths which will be reflected by the low-e coating on the outward facing side of the inner pane. Hence heat transmission in summer would be much the same as for Colorbond in which case go for the option that lets in most light.
My partner however feels that the Laserlite will inevitably let in more heat because it is translucent, hence should definitely not be above the windows.
Any thoughts on this?
