Ahh, these projects. We are having a Panasonice Whisper Lite bathroom fan installed. The roofers installed the vent about 10′ from where the fan will be placed. So the run of the vent tubing will be 10′. This seems like a long run and I’m concerned the fan won’t function as well. Does anyone know if it’s function will be impacted by this run length?
Joe Boston, MA
Replies
The Panasonic is a great fan. There may be a spec sheet in the box that gives recommendations on duct length. Ten feet doesn't sound terrible, but that's affected by the number of elbows and type of duct.
Al Mollitor, Sharon MA
I have one sitting right here that I'm getting ready to install in a BR remodel, but can't find anything in the instructions regarding duct length, etc. I've run lengths of at least 15' using expandable aluminum duct and not had a problem, as long as the fan was the Panasonic. I'm not sure about the Nutone or Broan, not that I would install either. Panasonic is the only way to go for customer satisfaction, if not performance.
I never met a tool I didn't like!
I got the Panasonic fan with a light so that I'd know when it was on.
Use smooth bore duct (PCV or expandable aluminum duct) not the coil crap and 10' should be no problem. As was previously stated, a lot depends on the number of elbows used. You say roofers installed, so I'm assuming it's going out the roof, so it's probably a straight shot from the fan to the vent, right?
It's always a topic of contention, but I always insulate my ducts (I use water heater insulation and foil tape) to prevent condensation. I've been rained on in my own bathroom until I insulated the duct and stuck it out the side of the gable end (it had been tacked up near the gable vent in the attic. Warm moist air would condense in the winter due to the cold attic and run back down to the fan.)
Fantech recommends *at least* 8' distance between duct and fan for their inline fans. They also recommend insulated flexible duct, I guess to avoid noise transmission. None of these are relevant to you of course....
I've seen this board recommend that you arrange your duct in a sideways S to prevent a chimney effect. I protested that this would lead to condensate gathering in the lower part of the S but was assured it did not happen in practice.
That's several pieces of advice (distance, flex duct, S) that contradict what one would think. I'd be delighted to hear contrary advice...
Joe:
I've got 5 of them in my new house and they are the best fan going.If you get on there web site they have a chart that will tell you the duct runs plus elbows.
My length was about the same as yours,but I had a few more elbows that added to duct length.I ended up going a size or two bigger on the fan and it has worked very well.
They are so quite that when I wired one up I couldn't even tell it was running till I saw the squirrel cage turning.
Greg