The Evening Purge Cycle explained

So there you are, laying in bed of a summer’s evening, sweltering and wanting to know why the cool air outside isn’t coming into the room.
You have a house full of energy with nowhere to go….and no, it’s not going to go out the windows because natural thermal energy wants to move vertically.

Now if you could only take the roof off for an hour or so…obviously you can’t!.. you do the next best thing, …..and take your pillow outside.


All, under the summer sun gets hot during the day and this is particularly so of buildings as they also store energy by absorption, to the extent that during the evening the building remains quite warm at night due to this retention.

Insulation for instance, great for resisting heat but not so great for releasing it and in fact is one of the reasons why homes remain quite warm after the sun goes down.
The temperature of an evening can be quite cool outside and yet the interior remains quite warm and this is simply because the heat is unable to escape.

Displacement!….you need a means of natural displacement….air needs to go out first before air can enter.
Much like a bank account

Warm air moves vertically,
Cool air moves laterally,
For the cool air to enter the room via the window,
Warm air needs to be removed.

Cathedral roof ventilation

Punch a hole in the ceiling…and the roof and you have a means of escape for the energy trapped in the bedroom…referred to as the evening purge.

You sleep better and when refreshed, you and your family are off to a better day because of it, and without running cost because it occurs…. naturally.

There are ventilation products that help you achieve this however be aware that products with moveable parts of plastic have a short life span and when they break down, they do so at a very inconvenient time.

The cooler the house at the beginning of each day, the more comfortable it is because it doesn’t carry the heat retention of the previous day into the next.

Condor Kinetic

Purge Vent
Condor Purge Vent
Air flow dynamic of roof ventilation

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