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(sPoNiX) wrote in message ...
My house is very hot, especially upstairs.

A perpetual problem, how to cool it. I wrote a pamphlet on this, there
are many ways, each of which can take anything from 1 to 10C off the
temp. Here's one explained briefly:

External air temp varies through the 24 hour cycle. The sun heats
things up, so the max outdoor temp is late afternoon, and the minimum
outdoor temp is at around dawn.

Houses have thermal mass, this means they have a tendency to even the
temperature variations out over the 24 hours. Therefore at night it is
usually colder outside than in, even in summer.

If a house is vented all night long, 2 things occur:
1. it is cooled
2. the thermal mass of the house is slowly cooled too, which keeps the
house at a lower temp during the following day.

How do you cool a house at night? By fitting locks to windows that
allow them to be locked in a slightly open position, enough to
ventilate but not enough to allow any means to gain entry. Simple
window security bolts can do this: fit an extra one to lock it ajar.
Venting is only really effective when you have a through path for the
breeze: only one window venting alone wont achieve that much.

Note that venting must occur for quite a long time to really be
effective. A house's thermal mass only changes temp very slowly.
Opening up for 10 minutes is not going to have much effect.

Regards, NT