Whole House fans have been around for over 40 years and offer a way to make a dramatic (I seldom use this word) difference to the comfort of a house in a warm climate. It does three things.
A large, slow moving fan is put in the ceiling of a house, usually near the centre or at the top of a flight of stairs.
- The fan removes a layer of warm air about 50 cm thick next to the ceiling. I have done smoke tests and the layer even moves over doorways.
- This air displaces even hotter air in the roof space and is usually exhausted though vents in the eaves off set from the windows.
- The air sucked out of the house creates airflows at every window, even on a still night.
The temperature in the roof space drops to near the outside air temperature – and you don’t need insulation.
The downside is that the fan does cost to run, but as it is not pumping heat like an air conditioner, the running cost is quite low.
The old “Queenslander” house design had high ceilings and vents in the roof, making them naturally a lot cooler than the modern dog boxes. But they need a lot of paint and maintenance, being made of wood.
