"Alen" wrote in message
Please keep in mind that the assumption is that the central air was on
all day, and downstairs is comfortable (73-75) and upstairs is
uncomfortable (83 or hight). Attic temp is 115 or higher.

Here are some ideas we're trying to entertain:

- Early evening, open up the windows on the second floor, run the whole
house fan while central air is on. After an hour or so, close the
windows, and let the ac do the rest.

- Early evening, open up a few windows next to the thermostat downstairs,
run the fan while ac is on. Cool air would go to the second floor and into
the attic. Warm air would replace the cool air next to the thermostat and
force it to keep the AC on which would then cool the upstairs and keep the
downstairs not too cold but comfortable.

- Any other ideas would be apreciated.

The best method is to get the AC working properly. Be sure you have plenty
of insulation in the attic and that it is well ventilated to start with.
The sun will really heat it up as you have seen.

Be sure filters are clean and not restricting air flow, blower is operating
at the proper speed. No leaks in duct connections, return vents are working
properly and open.

Running a whole house fan with AC is going to cost a bundle. You dehumidify
the air with the AC and the fan is just going to suck in warm moist air
You don't want that.

Be sure all the vents on the second floor are open all the way in rooms you
are using, closed partially in any room of the house not being used. Close
down the first floor vents just a little and see if it forces more air
upstairs. Allow some time between adjustments to see what affect it is
having.

Most people keep the vent registers wide open in every room. There is a
reason they are made to be adjustable, that is to balance the heating and
cooling through the house.
--
Ed
http://pages.cthome.net/edhome/