Has anyone tried what is suggested in the subject line?
My wife asked me to investigate other options after I told her whirlybirds were unlikely to be effective.
I said it would need to be ducted from the living space and may be useful then on cool, windless afternoons and evenings in summer. But then I got to thinking
1) why not use a bit of electricity to help move it? after all if it's windy enough to blow a whirly, it's windy enough to cross-ventilate through windows
2) if you are going to use an electric fan, why duct it to outside? the roof space has air gaps (corrugated steel) so a decent fan should be able to establish enough pressure differential to move it through those gaps
3) exhaust fans don't move much air but hmmm I have a great big fan in the ceiling that moves heaps of air already draws it from the living space-- it's the ducted heater.
So on those summer evenings when you've opened the windows but no air is moving -- how about it? Just disconnect the outlet duct from the heater, close the manhole cover and turn the fan on.
I am a little reluctant to hack into our brand new ducts without hearing from someone who has tried it before .