hey pup - I'm plenty versed in the building arena and am still in the game as opposed to siting on the bench armchair quarterbacking. "I most assuredly CAN make that statement " yes - but you'd be making an inaccurate one! "Once you know the CFM you then determine the lenght of run from the fan to the point of discharge and use the friction head loss tables to determine the correct size of duct. " Since you're so versed on this - how long is essdana's duct run? Did his/her builder installer use 3" or 4" ducting? What's the static pressure difference between 3" and 4" duct? What was it made from? What's the flow loss when using corrugated aluminum duct vs. smoothwall PVC? Do you need a slide rule for the math calculations ? Are there any elbows/bends in the duct run? How many ? It's clear you know how to do this: "Once you know the CFM you then determine the lenght of run from the fan to the point of discharge and use the friction head loss tables to determine the correct size of duct. " But, since you don't know the sizing, material , length and pressure loss of essdana's duct work install - you can't ACCURATELY say that the 40 CFM fan in question will overcome the static pressure of his/her duct work. Sure it works on paper with your slick tables - but the real world presents some curveballs. You certain learned this on your journey to Master status. And, you're not going to get to use anything but 4" duct for this fan anyway 3" if your builder /customer is cheap. So overcoming high static pressure with a clever oversized duct plan isn't really an option. Another thing - This fan we are talking about - 40CFM, is that a max. rating, average? At what static pressure was that measurement taken or is that maximum free air movement? If it was rated at free air , the second you add duct work (any kind) that rating is going to drop on a pretty steep curve as 40 CFM fans tend not to be high quality and accurately rated from the get go. So - simply going rule of thumb based on your "experience" using a few tables can get you into trouble in a real bathroom. That's my point. Your 40 CFM "idea" sized fan is great in your air conditioned office. What if the maker fudged' their rating and the thing only moves 30cfm when a duct is attached? What if two 90 deg bend are added into the duct run? How much restriction does the roof cap add to the system? How many room air changes is that 40cfm fan really going to produce at essdana's house? You can't answer that- you can only answer what the theoretical maximum would be based on your beloved tables and some educated guesses based on your experience. They are still guesses, and are no better than my guesses - so settle down boy.

I would guess you can, but one big fan will work more efficiently than 2 small ones. I can't say for certain without seeing in person.

i didn't go on a search for colors, but did need to find a 4-gang that had a standard switch in the first position. be aware that if you use a timer, it may not fit in some of these plate covers. i ordered one from kyle designs and my standard leviton timer did not fit through their decora sized hole. they were unwilling to work with me and just kept saying that all of their products are created based on caliper measurements and would not accept my tape-measure measurements (as if all of us have calipers lying around) and said that my timer must be oversized, which leviton says is standard decora size. home depot has some modular plate covers (leviton as well i believe) where you can choose the shapes of the switches you need and click the pieces together. these also did not work with a timer because of the overlap where the modular pieces click together... but it may be an option for you if you only have switches. not sure what colors they have available since i needed white... Here is a link that might be useful: the modular pieces at an online store - i have seen them in home depot too

In your last sentence of your first post your infer that a simple situation would of been black to black, white to white and ground to ground. So seems that what you were anticipating when you began removing the fan. But you also state while actually removing the fan, "It had three wires within conduit connected to it, those wires were orange, blue and grey. Then also connected to it was a separate set of wires coated in plastic, they were black, white, and a copper ground." Sounds like someone was trying to do a quick job during a commercial break or a halftime show maybe?? Anyway you say the orange, blue and grey wires from withing the conduit were definitely wired to the fan terminals? Or could they have been wire-nutted to the black and white wires from the NM cable? Then a pigtail from the wirenuts to the fan? Are the wires from within the conduit solid or stranded. Go CHIEFS