Hi Guys. I recently purchased my first home and there is a three inch dryer vent pipe that runs from the garage, through the wall and out of the roof. I used a 4 to 3 inch adapter with metal dryer duct to hook up my dryer (whirlpool duet). Is using a 3 inch dryer vent pipe okay as 4 inch is now the standard. I crawled up on the roof and it was blowing plenty of air out when the dryer was on.