How to replace and existing exhaust fan

Old 04-09-03, 07:37 AM
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Question How to replace and existing exhaust fan

I have a older house built in 1968. In our master bath which is rather large we have a old Nutone or something like that for out exhaust fan. If you close the door to the bath you get a lot of moisture build up. We don't have any paint peeling or wall paper pealing (well some of the border paper, but that is because I did not use border paste) so there really is no damage. Its just annoying with mirrors and the window. Usually we crack the door and we don't have the issue. I really think though a new bath exhaust fan would make a big difference.

As I said its a Nutone brand. Its a combo fan and heater unit with the wall knobs being a switch for the light and round knob to switch to fan, heat and fan and heat only. It in the ceiling near the shower/bath. The main problem with removing it is that it is the ceiling it is mounted on has a second floor flooring above it so I have no attic to get to it and I really don't want to have to rip up the floor upstairs. I do know that the metal box that contains the vent is nailed to the joists and that the vent tubing is connected there. So my question is....other than yanking the box out and such, what other issues do I need to consider to replace it? Particularly the electircal and such. Also, any other advice on replacing existing fans would be appreciated. Thanks!
Old 04-09-03, 10:17 AM
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See to find a similar fan.
Often, exhaust fans of the same brand will offer different size motors (larger CFM capacity) that fit the same housing.
Some people (including me) have bought complete same-brand fans just to upgrade and switch the motor without having to switch the whole fan. MUCH easier.
Check it out.
Good Luck!
Old 04-11-03, 09:42 AM
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OldGuys's advice is the best one.
In case you cannot find the replacement motor with higher CFM that will fit into existing housing(which was my case), remove the existing housing & take it to Bath supply to search for the closest match. In one side of housing, there's a flapper and a vent duct(either rigid or flex tubing) attached to it. Pull the tubing down as much as possible so that you can assemble it to the new one outside the hole. Vent duct goes from 3" up to 6"; yours is probably 3" or 4". Make sure new one has a same size opening in its housing. Purchase a tubing clamp and fasten it tight into the housing(Do not use duct tape).

As far as electrical connection, you probably has 14/3 wire going into it. Before removing the old motor, shut the breaker and label the wires so that you won't miswire to the new motor/light.

One more thing about the fan.....
Along with a sufficient CFM, another factor you should consider is Sones, the value of noise. Hardware stores usually has a display aisle for customers to turn on the vent fan and see how noisy it is. You shouldn't buy one higher that 3 sones. Mine is 2.5 sones and it still seems little noisy.
Old 04-19-03, 07:04 PM
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Thanks for the advice from both of you. I appreciate it. I am going to call Nutone as soon as I can.

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