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Every household can benefit from adding a preset bath fan timer

A bath fan timer will eliminate the need of remembering to turn the fan off, while providing adequate fan run time to dispose of moisture, odor, and stale air.



Bath fan timer switches

Each manufacturer, including the bath fan switch models shown, has a unique style and design to provide options to suit varying bathrooms and personal preference. But before you make a final purchasing decision, there are few things to know before upgrading from a common toggle switch.

Pre-Installation Information

When retrofitting electronic switches, a common 1.5″ deep electrical gang box can get crowded, which normally houses smaller bodied toggle and paddle switches. This may not be a problem for single box and switch combinations, but adding several electronic switches in multi-gang combinations, along with the additional wiring that exists, creates a packed environment.

Be careful not to pinch wires in such situations. At the same time, don’t cut wires too short to relieve some of the congestion. You may find yourself with too short of wires at some future upgrade.

WARNING: Electrical Hazard. Before beginning work, turn power off at the breaker panel or fuse box to avoid injury. Contact a certified Electrician or HVAC tech if unsure of your DIY capabilities.
TOOL TIP: Using a non-contact voltage detector is an easy, safe, and economical tool to check if voltage is present at the switch location.

With new construction or remodels in mind, consult with your electrician about the advantages of using a 2″ or deeper electrical gang box to allow more room for the larger electronic switches and wiring.

Lutron Maestro light switch compared to a toggle switch

When replacing a toggle switch with a fan timer switch, the wallplate will have to be replaced as well with a decora style switch cover.

Looking for a wall plate where you can easily add a custom color or pattern too? Check out the Legrand adorne™ series wall plates.

Single switch toggle and decora wallplates

Some fan timer models require a neutral wire. This is a circuit conductor that normally carries current back to the source, and is connected to ground (earth) at the main electrical panel.

If no neutral wire (commonly a white colored wire) is present:

  • See if a nearby junction box with a neutral wire is present. e.g. I wanted to upgrade several light switches that required neutral wires, but had no neutral wire at the switch. But the connecting lights had a neutral wire running through the junction box, so I was able to tie into that neutral wire connection and easily push a short run of wire through the conduit back to the switch box.
  • Will have to commit to a timer switch model that doesn’t require a neutral wire.
  • Contact an electrician to run a neutral wire to needed switch box.

Lutron Maestro Fan Timers

The Lutron Maestro switch lineup offers a clean and elegant looking switch with the right amount of features. The small toggle button on the right scrolls between time sequences and the large center button turns the switch on/off. Double click the large button to override the countdown and have constant On.

**View complete wiring instructions at Lutron


  • An array of colors to choose from.
  • 6 countdown increments and continuous ON.
  • No neutral wire is required at the switch location for single pole models.
  • Non-polarity specific – Connect either in / out hot wire to either screw or push-in connection. No worries of miswiring.
  • Screw and push-in terminals for wiring connection flexibility.
  • Dual switch (fan and light / MA-L3T251) available. (i) A dual switch can combat overcrowding in a retrofit situation with a shallow 2 gang box. Use a dual switch only, then use a decora blank in the other location. (ii) for a single electrical box, the light and fan can now be separated (additional wiring may be necessary) instead of both being powered ON by the same switch.


  • None, in my opinion. We have Lutron countdown timers in all our bathrooms and they have been very reliable, while adding an appearance improvement to a room.
Lutron Maestro MA-T51 bath fan timer
Lutron Maestro MA-T51 bath fan timer Lutron Maestro bath fan timer back view and wiring terminals Lutron Maestro countdown timer wiring Lutron Maestro countdown timer break-off tabs Lutron Maestro countdown timer operation instructions Lutron Maestro MA-L3T251 timer switch

Leviton Preset Fan Timers

The Leviton fan timer switches have a BOLD 5-button design. Easy to see – and uncomplicated.

Be sure to purchase one of the model numbers listed. The same design of timer switch is also sold under numerous other model numbers for light switch use only, but they aren’t load rated for fan use.


  • 3 face-plates included with LTB Series (white, ivory, light almond)
  • Advanced Programming Feature – Time sequences can be re-programmed without buying a new timer switch. A new matching time sequence faceplate is recommended.
  • Pre-wired – (i) eliminates or reduces the need for additional wiring. (ii) color coded wiring simplifies wiring connections.
  • Timer over-ride for continuous ON (24 hour shut-off).


  • All timer switches for fan use are 3 way capability by default, therefore requires a neutral wire at the switch location.
  • Pre-wired harness – (i) reduces wiring flexibility and adds clutter. (ii) thick stranded wires for the black, red, and ground (optional) can make wiring more cumbersome compared to standard and much smaller diameter 14 awg solid wire.
  • Single switch application only – no dual switch applications.
Leviton preset countdown fan timer
Leviton preset countdown fan timer Leviton LTB30 countdown timer backview Leviton preset countdown fan timer wiring Leviton preset countdown bath fan timer operation Leviton preset countdown bath fan timer timing change Leviton preset countdown bath timer cover color change
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