I just wanted to share with you this e-mail I got at work. (Luckly) we do not have condition-air, so there are people complaining about hot temperatures. Someone decided to write some suggestions to all of us…enjoy it (sorry for non physicists if you do not get the fun)

Several of us (perhaps the majority) feel uncomfortable with the
temperatures developing in our building during hot spells like the
present one. That is, we would prefer the building to be cooler. The
following contains some recommendations to you that will help us achieve
this goal.

The intrinsic thermal time constant of the building is large enough
(several days, probably) that it would be thermodynamically a simple
matter to maintain internal temperature at a value not exceeding the
daily average outside temperature (about 23C at the moment).

Experience shows that the actual temperature in the building is often
much higher. The cause can be traced to the practice of preferentially
opening windows and exterior doors when the outside temperature is at its
highest.

{\bf Excercise}. Your open window (aperture: 1 m2) allows an airflow of
1 m/s to enter the building at a time when the outside temperature is
30C, the inside temperature 23. Compute the heat load you are imposing on
the inhabitants.
[hint:
http://www.efunda.com/Materials/common_matl/show_gas.cfm?MatlName=Air0C]
To put the result in perspective: this is about the yearly average
heating requirement of a 70m2 apartment.

It should not come as a surprise, then, that the building quickly heats
up even when only fraction of the inhabitants follow this practice.

Of course, you experience a cooling effect when exposed to an airflow
from your window, even if the air temperature is rather high. But
consider that this effect is absent in most of the volume away from your
window. After passing by you, the hot air, following its nature, floats
up to the directors' level (the 3rd floor of our building). In addition,
doors opened on the lowest floor allow cool air to escape from the
building, being replaced by hot air entering at the higher levels.

If the physics involved here does not appear transparent to you, you
might consider whether a physics degree was actually the right thing for
you, respectively if you should aspire to obtain one.

{\bf Recommendations}
- Close your windows and outside doors when the outside temperature gets
higher than the building's interior.

- To reduce the heat load on your office, consider using the {\em
blinds}. With thermodynamic aforethought, these have been placed on the
outside of the windows, and experience shows them to be quite effective.

- When you see apertures opened in the hallways, coffee area etc, feel
free to close them under these same conditions. If this meets with
questions from others (the need for `oxygen' or `fresh air' is sometimes
advanced in this context), you can politely point out that this is part
of the institute's carefully thought-out measures to avoid overheating of
the building. Explanations of the physics take more time, and experience
shows that they often do not achieve their goal.

Of course, variation exist in people's subjective appreciation of
temperature. This can be accomodated under the following rule of conduct:
- Feel free to open your windows, outside doors or raise the blinds on a
hot day, but show your consideration for other inhabitants of the
building by {\em keeping your office door closed} whenever doing so. If,
for psychological or physiological reasons you feel the need for
increased airflow under these circumstances, consider the use of a fan.