Leviton Countdown Timer Switch for household lights, heaters and exhaust fans, 30 min, 1-2-4 hour, No Neutral Wire Required, Single Pole, 15A, 1/2 HP/9.8A Fan/Motor, DT104-1LW, White

Why I installed it

After one too many mornings finding the bathroom exhaust fan still humming from the night before, I swapped the standard switch for a Leviton countdown timer. I also added a second unit on the garage lighting circuit so the lights aren’t left blazing all evening. The idea is simple: pick a preset time (30 minutes, 1 hour, 2 hours, or 4 hours), and the switch handles shutoff automatically. In practice, it’s been a practical little upgrade that saves energy and reduces moisture without adding complexity.

Installation experience

This is a single-pole, 120V timer, so it replaces a standard on/off switch in a straightforward way. The device arrives with two black leads that are interchangeable between line and load—a small detail that takes some pressure off less experienced installers. You still need to identify your hot feed and turn off the breaker before you begin, but if you mix the two black leads, the device will still function correctly.

A standout feature is its no-neutral option. If your wallbox doesn’t have a neutral, Leviton includes a green flex sleeve that allows the timer to reference ground. If you do have a neutral in the box, you can remove the sleeve and connect to neutral instead. Either way, a proper equipment ground is required for installation—plan accordingly if you’re working in an older home that lacks a ground in the box.

Fitment-wise, the body is slimmer than some older electronic timers, but it’s still bulkier than a basic toggle. It slid easily into a modern plastic box with a couple of pigtails, but in one older single-gang metal box with multiple splices, I had to spend a few extra minutes tidying conductors to make everything sit right. In multi-gang boxes or deeper boxes, there’s ample room.

A few quick tips from my install:
- Use appropriately sized wire connectors; there are no screw terminals here, just pre-attached leads.
- Pre-bend and stage the conductors at the back of the box; it reduces stress on the timer body as you mount it.
- If you have a neutral, use it—it’s often the cleaner approach even though the no-neutral option works.

Day-to-day use

Operation is dead simple. Tap the time you want and the load turns on; when the timer expires, it shuts off. There’s no “always-on” mode, and I consider that a feature—not a bug—for ventilation and lights that should never be left on indefinitely. If I need to cancel early, I just tap to stop it. Each press has a positive, tactile feel, and the internal relay gives a single, decisive click at activation and shutoff. It’s audible in a quiet bathroom, but not loud; more reassuring than annoying.

A small status LED provides a subtle visual cue when the timer is active. It’s bright enough to confirm the state from a glance, but it doesn’t light up a bedroom at night. The face presents as a clean Decora-style device, so it blends well with other modern switches and dimmers. If you care about color matching, Leviton’s swappable face kits are a nice touch; I stuck with white, but the option is there.

In daily use, the presets provide sensible options. Thirty minutes is perfect for a quick dehumidify after a shower, and I use the 1-hour preset often in winter. The 2- and 4-hour buttons have been handy for garage lights when I’m working on a project or moving things around.

Build quality and design

The switch feels well made, with crisp button action and a firm relay. The mounting strap and back body are plastic rather than metal, which keeps weight down but doesn’t feel quite as rugged as metal-strapped devices. Once it’s installed, there’s no wobble or rattle, and the face aligns cleanly with a standard Decora wallplate. It presents a professional finish.

If you’re rough on hardware or installing in a location where switches get bumped often, a metal-strapped alternative might inspire more confidence. For typical residential bathrooms, laundry rooms, and garages, the Leviton’s construction has been perfectly adequate.

Compatibility and ratings

A big part of choosing a timer is matching it to the load. This one is versatile:
- 15A resistive (great for many heaters and heat lamps within rating)
- 600W LED/CFL, 1800W incandescent/halogen
- 1200VA magnetic/electronic low-voltage and fluorescent
- Up to 1/2 HP (9.8A) motor loads

In the real world, that means bathroom fans, attic fans (within rating), towel warmers, heat lamps, and general lighting are all fair game. It’s single-pole only—no three-way support—so if you have two switches controlling one light, you’ll need a different solution. It’s also for 120V circuits; don’t use it on 240V baseboard heaters or other high-voltage applications.

One note on heaters: many baseboard heaters are 240V and require a double-pole control. This timer is not for that scenario. On 120V resistive loads under 15A, it’s fine.

Where it shines

• Bathrooms: The ability to run a fan for 30–60 minutes after a shower without thinking about it reduces moisture and helps prevent mildew. No more forgetting to come back and turn it off.
• Garages and utility spaces: Set-and-forget lighting when you’re likely to walk away mid-task.
• Small motor loads: Within the 1/2 HP rating, it’s a safe way to time fans and similar devices.

What could be better

• No “hold” or indefinite on mode: I prefer it this way for ventilation, but some users may want an override. If you need that, look for a timer with a dedicated ON mode.
• Depth in crowded boxes: It’s not the bulkiest electronic timer I’ve installed, but in shallow, older boxes with many splices, plan for some wire management.
• Plastic mounting structure: It’s sturdy enough once installed, but doesn’t feel as robust as metal-strapped options.

Safety and setup reminders

• Kill power at the breaker and verify with a non-contact tester before touching any conductors.
• Confirm the circuit voltage and load type; stay within the published ratings.
• This device requires an equipment ground. If your box isn’t grounded, consult an electrician.
• The two black leads are interchangeable, but proper identification of the feed and load is still good practice.

Alternatives to consider

If you need a three-way configuration, look for a companion-ready or networked timer rated for multi-location control. If an indefinite ON mode is non-negotiable, choose a model that explicitly supports a manual ON function. For extremely tight boxes or commercial environments, a metal-strap timer might be worth the trade-off in price.

Verdict and recommendation

The Leviton countdown timer is the right kind of upgrade: simple, reliable, and genuinely useful. It solves a common household problem—lights and fans left on—with minimal learning curve and clean aesthetics. The no-neutral option makes it accessible in older homes (provided you have a proper ground), and the interchangeable line/load leads keep installation approachable. Day to day, the tactile buttons, quiet but decisive relay, and sensible presets make it effortless to use.

I recommend it for single-pole bathroom fans, garage lights, and other 120V loads within its ratings. It’s especially compelling if you want to reduce moisture and energy waste without adding smart-home complexity. Just be aware of its limitations: it won’t do three-way, it doesn’t offer an indefinite ON mode, and the plastic body isn’t as tank-like as some metal competitors. With those caveats in mind, it’s an easy, worthwhile improvement for most homes.