A  room, 30' x 60' x twenty feet in heigth, holds an indoor swimming
pool with an 800 sqare foot surface area.   When in use, the pool is
heated to 84 degrees.  Next to the swimming pool is a small Jacauzzi,
which when in use, is heated to 105 degrees.  Mold/mildew are forming
on the ceiling.  I have been told a wall fan, taking air from the room
to the outside will solve my problem, something to do with turning the
36,000 cubic feet of air over a number of times per hour.  What are the
proper size and specifications for the fan?

carl...

Some people use whole house fans to cool the house
instead of air conditioning, and these fans turn
over the house air 3-4 times an hour. For removing
humidity, however, bathroom fans are designed to
replace the air 10 times an hour. Given the size
of your room, this means the fan needs to be rated
at about 6000 CFM (cubic feet per minute).

Fans that size would tend to generate more noise,
so you might want to consider using two fans rated
at about 3000 CFM. You will also need to have a
passive vent which would allow for the unrestricted
airflow to allow the fans to do their job.

This article on whole house ventilation on the
DoItYourself.com website gives the rule of thumb
for the vent size:

"the rule of thumb is to divide the capacity of the
 fan in CFM by 750 to arrive at the total square
 footage of...ventilation area needed"
http://doityourself.com/aircond/coolingoptions.htm

6000/750 = 8 square feet of vent openings, total.
Screening or grilling on the vent can reduce the
airflow by up to 50% (in the case of insect screen),
so vent size should be adjusted accordingly. See
this consumer alert from the R. E. Williams site:
http://lib1.store.vip.sc5.yahoo.com/lib/rewilliams/consumeralert.html


Two fans such as this 20" one on the R. E. Williams
site would be sufficient, running on high:
http://www.rewci.com/rewilliams/20wholhouswi.html

Here's a 30" fan which will handle 5800CFM:
http://doityourself.com/store/6279061.htm

Here's another 30" which is belt-driven (this tends
to isolate and reduce the noise, vs a direct-drive):
http://www.arhomecenter.com/user/catalogue/product_detail.asp?ProductId=20418

And on this page is a 36" which can handle 7800CFM,
as well as another 30":
http://www.trylock.com/roofpower.html


If you have no attic, as such, to work with, you 
can hire a contractor to create a wall fitting to
work with these fans, as well as suitable venting.
The contractor may have alternative suggestions as
to the type of fan to use, but the specifications
will need to be in the range I've discussed.


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Additional information may be found from an exploration of
the links resulting from the Google searches outlined below.

Searches done, via Google:

"ventilation fan" "cubic feet per minute
://www.google.com/search?q=%22ventilation+fan%22+%22cubic+feet+per+minute

"ventilation fan" "cubic feet per minute" OR CFM
://www.google.com/search?q=%22ventilation+fan%22+%22cubic+feet+per+minute%22+OR+CFM

"whole house ventilation fan" 30
://www.google.com/search?q=%22whole+house+ventilation+fan%22+30