I installed a Nutone fan about 8 years ago rated for 100 cfm. The performance went down hill fairly rapidly over the past 6 months. I finally did the tissue test to see if it would hold, of course it didn't! The fan has subsequently been cleaned along with the discharge pipe. The air being drawn out is marginally holding the tissue paper.
How do you really know when enough is enough and replace the unit?
Is there any advantages in buying a fan for greater than 100 cfm's when the bathroom really does not need it? The configuration is roughly 80sqft with just a hopper and a shower/bath combo. Something I have been looking is manufactured by a company called FanTech. The cfm is overkill at 230 but the thought was to put an exhaust port within the shower alcove and then another port with a light in the main run of the bathroom.
Any insight and guidance would be appreciated.