Wanted to ask what folks might suggest for adding a non-switch type timer to a bathroom fan setup. I say non-switch, since the existing box is completely full with a dimmable vanity switch and a 3 rocker for fan/light/nightlight. no room to add a 3rd switch (plus it's a tiled wall) otherwise I'd do that. First thought that comes to mind is more on the automotive side, where a programmable timer can kick in after the vehicle turns off to run whatever accessories for X minutes. Obviously more on the back end with relays and such, but the concept is what I'm getting at.
Same general scenario but for this it would be turning on the bathroom fan as usual but when turning off the switch that kicks a timer into play for an hour let's say.

Any ideas?


  • Every bathroom fan I've ever come across has had a timer built in anyway.
    – Chenmunka
    Oct 17, 2022 at 22:23
  • Is there a reason you don't want the nightlight to simply be on all the time? Oct 18, 2022 at 3:25
  • I’ve never seen a bathroom fan that had a timer on it. that is usually always a endpoint switch. Would be very nice in this scenario that I am thinking of! Oct 18, 2022 at 13:56
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    I am still mulling over the idea of working with the existing outlet box. Just a pain in the butt to work with since it’s all old Work, shallow boxes. Not that much room to work with. If I can buy the wires or simply leave out the night light altogether, then it would take it down to a single switch for light and one for the fan with timer, and I’ve seen a number of options for that. Decisions, decisions … Oct 18, 2022 at 14:00
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    Neutral in the box. Suppose I’d prob do one or the other humidistat or timer. But it would have to have the ability to turn on lights in the same outlet space. Oct 19, 2022 at 13:29

1 Answer 1


You'll have to replace the dimmer, but it is possible to squeeze all this control into 2 gangs

Given your constraints of 2 gangs, 4 devices (vanity, overhead, nightlight, fan), dimming control of the vanity light, and either delay-off timer or humidistatic control of the bath fan, what you want actually is possible, but it has a few caveats.

First and foremost, the delay-off timer options for bath fans in the US are quite limited, with the Broan-NuTone DT100W being the only wallbox timer I can find that implements the behavior you want for the fan. While it can control a light fixture, it does not provide control of the light fully independently from the fan. If that's not a satisfactory approach, you'll have to go over to humidistatic control, since you can't add more box space readily and UL listed timer relays don't fit into shallow two-gang boxes. (If you had the space for it, a Macromatic TE-8816 could handle the fan timer duties without an issue, but it's designed for DIN rail mounting, which makes it a bit big for stuffing in the back of a two-gang wall box.)

If you want a humidistatic fan instead, you can make this work more easily, with the fan control being replaced by a Leviton DHD05. This device provides a light tapswitch and a fan humidistat in the same package, giving you fully independent control of the light and fan. (It also doesn't require a neutral, but since you have it available to you, you're best off using it for this installation.)

Either way, you'll need to swap out the existing dimmer for a dimmer + switch combo, such as the Lutron MA-L3S25. This provides you with control over the vanity lights and your nightlight function. (The Lutron Maestro dimmer/switch combo I suggest also provides a nightlight/locator function of its own, so you may want to keep that in mind when deciding whether to use the nightlight function of your fan.)

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