Roof sprinklers

While not yet common in Australia, roof mist cooling systems are a popular method of cooling, particularly in certain parts of the US. These systems are primarily installed on commercial properties, but in recent years have started to find their way in to residential applications.

Roof sprinkler 
Roof mist systems help dissipate heat from the roof.

How roof sprinklers work

Roof sprinklers work by spraying water at predetermined intervals on a roof’s surface. As the water evaporates, it cools the roof and helps to lower the temperature of the roof tiles and the ceiling cavity beneath it. The principle is similar to the way the human body cools itself with perspiration.

These types of systems can also be set up to operate automatically – either on a timer, or connected to an automatic temperature sensor which triggers the system whenever it gets too hot.

Efficiency and other uses

One of the best arguments for roof mist systems is their usefulness in helping to protect houses in bushfire-prone areas. While they only constitute a small part of a complete defensive bushfire strategy, roof sprinklers can help to protect a home by helping to dissipate heat, and by dousing roofing and gutters on demand.


Of course, the shortages of water in some parts of Australia mean that these types of system aren’t always appropriate just for cooling purposes, and can prove wasteful if not properly considered. For the sake of bushfire protection, roof sprinkler systems should ideally be connected to your own rainwater tanks through metal piping, not plastic (which can melt).

These systems can also lead to a build-up of limescale on your roof – particularly if bore water is used.

  • Helps protect against bushfires
  • Cools the top of the house
  • Relatively easy to install
  • Can easily be automated
  • Uses a lot of water
  • Not a substitute for good design
  • Hard water or bore water may deposit lime scale on the roof