Product review (1 stars): loud, Loud, VERY LOUD! Did I say LOUD?
Hi:

OK, I'm biased... and very knowledgable too.  The specs on this unit say it only puts out approx 2 sones on low and a max of 5 sones on high. Hah! Well, I think they those at Zephyr are either: 1) Putting out faulty products. 2.) Not telling the truth. 3.) Since Zephyr Ventilation is not a member of the HVI (Home Ventilating Institute (HVI) who  represents manufacturers of residential ventilation products from the United States, Canada, Asia and Europe and who certifies products found in 98% of all homes (and no, I don't work for them) they have no one checking their math or making sure their products actually comply with ANY standard, Zephyr is getting away with putting out very noisy products with ZERO oversight.

Well, as an audio guy for nearly 50 years and also a product designer, I can tell you (based on my own listening and the use of a dB meter (in both the A and C weighted scales) that that this product's minimum sone rating is nearly 7, NOT 2, and nearly 8.5 on high. Not even close to their stated 2 and 5.

Additionally, the switches are of poor, jerky quality, the exceptionally hard-to-find lightbulbs are very glary and exceptionally short-lived.  Back to the store it goes.

As if the above revelations aren't bad enough, 4 unanswered phone calls & messages left to Zephyr's Tech Support tells the rest of the story. DO NOT BUY - ZERO STARS if possible, is my whole-hearted recommendation.. unless of course you like wasting your money & having no tech support.