Traditional Solutions to the Hot house

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roof heat extraction

The Heat problem

Roof heat extraction

This heat problem has been recognized for a long time, and there have been various methods tried over the years, they include:

  • Fitting of eave vents
  • Wind-operated ventilators (whirlybirds)
  • Adding more insulation to the ceiling
  • Installing ventilated skylights
  • Even installing whopping big air conditioners or air coolers.


All have had some measure of success, but none really addresses the cause of the problem at its source, and therefore effectively treats the actual cause.

Even fitting a big ducted air conditioning system inside the roof space finds that the air conditioner is often working against itself, trying to make the rooms below cooler and more comfortable, whilst operating in, and heating up the roof space.

The more heat that accumulates within the roof space, the harder it is to cool the rooms below.


Effectiveness of Traditional Solutions

Most roofs have an almost static air volume inside them.  The air inside the roof hardly moves at all. Even with a wind-operated ventilator fitted, most of the air stays where it is, apart from the very hottest air that gets sucked out on a windy day.  On hot, still days, when there is no breeze, almost no heat is extracted whatsoever.

The fitting of eave vents can help the situation, as there is then an opportunity for the heated air to be replaced by cooler air from the eaves, but generally, the air flow from wind-powered ventilators is so small, that the overall effectiveness is not that great.

Ventilated skylights are another solution that is often tried.  They can allow hot or stuffy air inside the room below to be removed, but the problem of a hot air mass above the room, in the roof space, still remains.

And using big air conditioners can cost you a fortune to run, particularly if they are running on peak electricity tariff, which occurs when you run them during the day and the evening.


The Solar Ventilator Solution

Solar ventilators are made to extract the heat fast, and at exactly the time when the heat needs to be extracted – that is, when the sun is shining!  Because solar roof ventilators run all day during hot weather, starting from early morning, the roof space never actually gets the chance to heat up.   Therefore, it cannot radiate heat down through the ceiling, and make the rooms below feel hot and uncomfortable.

More on Solar Ventilators here…

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