Looking for quietest, most energy efficent 5" inline fan to buy.

@GrowCN I took your advice & i went with a SystemAir Revolution EC Vector Fan / 150 / 6" inch / Controller. But when came it seems it's for a room & I have a 4x4 tent lol, I cant see where you would string it to the top of the tent. I had to send the 1st fan I got back (at a cost of £70) Im not having much luck lol. I need to utilise this platform more I think. I'm moving to a place with alot more space this winter where I can out the tent in the garage & build a room for 20/30 . I'm gonna do a few runs in the tent then when i think I'm ready do both, the only thing I've grown in my life is sick of paying for weed. Thanks for your help mate.

I LOVE the AC Infinity Cloudline fans. One thing that really helps keep a fan quiet is to go oversize. Air moving quickly makes noise so slow is quiet. Instead of a 4" fan running at full power get a 6" and run it at a slower speed. It will be much quieter and the 6" filter will do a better job absorbing odors. It is more money but I love their digital controls. You can set the fan to be controlled by hi or low temperature or humidity. This is great for maintaining temperature when your lights are off and the fan doesn't need to run versus when the lights are on and you need cooling. The same with humidity. Soon after watering the humidity in the tent will rise and the fan will come on automatically. Then when the humidity drops the fan turns off. VERY handy to have.

Cloudline fans are quiet. Get a an inline fan with a DC motor. Then get some insulated ducting . That really reduces the sound.