Solar water heater Installations

Meeting Building Code Requirements

If you want to install a solar water heating system, you will need to apply for a building consent. The building consent application must demonstrate how the solar water heating system will meet the performance standards of various New Zealand Building Code clauses.

The Acceptable Solution for Solar Water Heaters G12 / AS2 provides one way of meeting the performance standards of the NZ Building Code when specifying and installing a solar water heater. If the proposed solar water system falls outside the scope of the acceptable solution (G12/AS2) you can refer to the guidance published by MBIE on alternative solutions for solar water heaters.

Please Note: The Acceptable Solution does not cover installation of a water tank on the roof and some other installation situations. It is up to the supplier or installer to provide adequate proof that the system and its mounting arrangements will meet the performance standards of the Building Code.

Loading and Size

Most roofs are designed to carry minimal additional loads. Therefore the Acceptable Solution places limits on the load density (22 kg per m²) and the size (4 m² of the roof), i.e. 88kgs over 4 m² of the roof. If a heavier or larger panel is proposed, then you will have to employ an engineer to assess the roof structure and to calculate how much additional load the roof structure can carry.

Elevated Panels

In some situations, a solar panel may need to be elevated above the roof surface either to maximise its efficiency (angle to the sun) or to allow the roof cladding to be washed by rain or accessed for cleaning (roofing warranty requirement). The accumulation of dirt and debris can lead to corrosion of metal roof claddings. The supplier or installer needs to provide adequate proof that system and mounting arrangements can cope with the additional wind loading and meets material maintenance (durability) and performance standards.