I work in the energy efficiency area of a small el...

I work in the energy efficiency area of a small electric utility. I understand the value of Whole house fans and have two quiet cool fans. The 2250 is for small vacation home and the unit is very quiet. It s quiet enough that my wife likes to run it a lot for the cool breeze it creates in the house. The other is for our larger house. The noise with the 3100 is more noticeable and consequently the fan is used more sparingly. But I have to say both of them are more quiet than most whole house fans I ve ever experienced. Installation was straight forward and pretty easy if attic access is not a problem. I would both recommend and buy these again.