I am opening a new child's soft play centre and need 4 x 250mm fans installed through a Kingspan insulated wall in the premises to introduce clean air into the building. I would be looking for fans to be energy efficient and run on low voltage if possible as they will not be running unless the gas heater is in use or the building is very warm due to the hot weather etc. I would require these to be wired in such a way that when the switch is turned on all fans operate. Regards, Allan Ramsay Kids-R-Us soft play limited.