Installing solar-powered roof ventilation

Some time back we installed a R3.5 batts in the roof of the original half of the house, along with reflective foil. Despite this, the roof space still gets very hot in summer, and after a run of really hot days, we can feel the heat radiating down into the rooms over night.

For this reason, it’s highly recommended to ventilate the roof space during summer. While traditional ‘wheely birds’ are an option, what I’ve read suggests that they simply don’t draw through enough air in an hour to make a real dent on a typical roof.

We therefore focused on an active ventilation system. There are heaps of different options, but my search narrowed down to two products, both solar-powered:

• Solar Star
• Solar Whiz

In the end, we went for the Solar Star, which seemed like the better fit for our needs. For the size of our roof, a single Solar Star RM 1200 model was the recommended option, and we  bundled in a thermostatic control.

The Solar Star unit, sitting on our table before installation.

Installation was simple enough. It comes with a plastic flashing suitable for a corrugated roof, plus the necessary screws and instructions. We further simplified the process by fitting the unit directly under the ridge capping, which allowed us to skip a lot of the more fiddly waterproofing steps.

The flashing installed for the Solar Star, looking through to the reflective sarking underneath (which we cut a hole through at the end of the job).

All up, the job took about an hour, most of which involved getting the tools onto the roof and generally stuffing around.

The Solar Star installed, just under the ridge of the roof. Not pretty per-se, but far from ugly.

Ideally, at this point I’d be able to report (with graphs!) the roof temperature before and after installation, compared to the outside temperature. But life has been busy!

So I can report that the fan runs steadily and quietly, and I’ll post later with a purely qualitative assessment of the impact.

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