NZ Examples of businesses and homes using white roofs
NZ businesses have been quietly using white roofs as passive cooling for many years to reduce heat loads on roofs and reduce air conditioning bills
The Sylvia Park shopping centre in Auckland
Sylvia Park shopping centre in Auckland, built around 2006, is a good example of a white roof deliberately chosen by its owners for as an energy efficiency measure. The white roof cuts down on the amount of heat entering the building through the roof and significantly reduces the electricity consumption by the air conditioning to keep the interior cool. The energy bill is also reduced by using Low E coated glass on skylights to cut down solar heat into the building while still harvesting light from the outside and reducing energy demand by lighting, and "free cooling" air conditioning to circulate air without additional mechanical cooling when outside conditions allow. The tenants benefit from the air conditioning savings.
The Sylvia Park white roof has an area of approximately 40,000 square metre.
The satellite photo (Google Earth) on the left shows the Sylvia Park complex, bisected by the motorway that runs over the top, with the white roofs showing in stark contrast to the bitumen paving. The photo at right shows part of the roof seen on the right of the satellite photo. Note that the small concrete carpark in centre-left also shows up fairly white because concrete has a higher reflectivity than the blacktop bitumen.
Deliberate choice of pale coloured roof for heat load management
PAK'nSAVE specify white ‘Titania’ to reduce heat loads on their stores
This PAK'nSAVE store on Lincoln Rd, Henderson, Auckland, has a roof area of approx 9000 m2
All Mainfreight buildings have white roofs to manage heat loads. Also to reduce structural expansion issues in big areas of roof
This 12,000 square metre depot is on the way to Auckland Airport
The owners of Seamount deliberately chose an off-white roof on this 15,000 square metre warehouse in Auckland, the largest warehouse in the southern hemisphere.
Telecom engineers deliberately painted roofs white in the 1980s to reduce solar heat gain, to avoid the cost of additional air conditioning plant when exchanges were replacing their old mechanical switching gear to the newer computer switching which generated significant additional heat
The vast majority of Fonterra’s stores and large process halls already have white or very light coloured roofs to manage heat loads on roofs and reduce air conditioning usage.
Waihi Beach has a higher proportion of white roofs. The houses sampled here were all in a range of about 1.5 kilometres along the coastal strip. In one street, 19 out of the 101 houses have white or off-white roofs. That's about ten times higher than the rate in Auckland. It seems that people there go white because they feel the heat there in summer, and some deliberately choose white knowing the benefits.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -