Be sure you have enough ventilation in your attic space to exhaust the air that the fan will be pushing into that area. Getting rid of the very hot air in the attic is part of the way whole house fans work, besides drawing the cooler outside air through the living areas of your house. I live in the Allied Gardens above Mission Valley and have had a whole house fan for over 30 years. They work great if you wait for the cooler evening air coming up the valley from the coast and then open then windows and then turn it on. We had a few instances where the fan has been turned on accidentally with no doors or windows open, the fan pulled air down the chimney and blew ash from the fire place into the living rooms. Big mess to clean up.