Quick Answer: The right hot tub timer depends on voltage, not preference — a hardwired 120V hard-shell spa pairs with the Intermatic PB913N mechanical panel timer ($57, 20A, the industry-standard part spa electricians install), a plug-and-play inflatable spa works with either a Woods 50012WD mechanical plug-in timer ($15-20, no app needed) or a TP-Link Kasa KP401 WiFi smart plug ($13-17, adds app scheduling), and a hardwired 240V spa needs a dedicated 240V-rated unit like ThermoMart’s 40A smart outlet box ($108) rather than a standard smart plug. Match the amp and voltage rating to your circuit before buying — this is the one accessory category where the wrong pick is a fire-code problem, not just a bad fit.
This is a straightforward electrical-safety category dressed up as a convenience buy. The three real options below cover 120V mechanical, 120V smart, and 240V smart — pick the row that matches your spa’s actual circuit.
Hot tub timers by the numbers
- 20A at 120V is the Intermatic PB913N’s rated capacity, per its official 24-hour panel-mount timer specification — enough for most hard-shell spa pump circuits, but always confirm your circuit breaker’s amperage before wiring one in.
- 15A / 1875W is the maximum load for both the Woods 50012WD mechanical plug-in and the Kasa KP401 smart plug, per their manufacturer listings — fine for a single inflatable-spa pump/heater unit, but check your spa’s rated draw first since some inflatable units pull close to that ceiling.
- 40A at 240VAC (10HP) is ThermoMart’s rating for its dual-hotline smart outlet box, built specifically for hardwired 240V spa and pool-heater circuits that a standard 120V smart plug cannot safely handle.
- 24 on/off cycles per day is standard on both mechanical timers here (Intermatic PB913N and Woods 50012WD), typically adjustable in 15-30 minute increments around the dial.
- $30-$60/month is the typical electricity range for an inflatable spa we break down in our hot tub running cost guide — a timer that limits heating to set hours is one of the few lower-cost levers in that budget, behind insulation and a well-fitting cover.
Which timer fits your hot tub?
| Your spa | Timer type | Rating | App control | Typical price |
|---|---|---|---|---|
| Hardwired hard-shell, 120V circuit | Intermatic PB913N panel timer | 120V / 20A | No | ~$57 |
| Inflatable / plug-and-play, budget | Woods 50012WD plug-in timer | 125V / 15A | No | ~$15-$20 |
| Inflatable / plug-and-play, smart | TP-Link Kasa KP401 | 120V / 15A | Yes (WiFi) | ~$13-$17 |
| Hardwired hard-shell, 240V circuit | ThermoMart 40A smart outlet box | 240V / 40A | Yes (WiFi) | ~$108 |
Prices checked August 2026 across manufacturer and retailer listings. If you’re not certain whether your spa runs on a 120V or 240V circuit, check the breaker panel or your owner’s manual before buying — this is the detail that actually matters here, more than any feature.
1. Intermatic PB913N — Best for Hardwired 120V Hard-Shell Spas
Intermatic PB913N 24-Hour Panel Mount Timer
- The standard mechanical time clock installed by spa electricians on 120V hard-shell spa circuits.
- Rated 120V, 20A — panel-mounted inside the spa's equipment compartment, not a plug-in device.
- 24-hour dial with adjustable trippers set the on/off cycle; no app, no WiFi, nothing to lose signal.
- Keeps its schedule through a power outage — you just reset the clock face to the correct time.
Getting the wiring right the first time matters more than any accessory — if you’re mid-install and waiting on a part to arrive, you can try Prime free for 30 days and have it shipped in two days instead of waiting a week.
The PB913N is a panel-mount unit, meaning it’s wired into the spa’s equipment bay rather than plugged into an outlet — this is a job for a licensed electrician or an experienced DIYer comfortable working inside a spa pack, not a beginner project. It pairs naturally with a spa that already has its pump and heater hardwired in, and it’s the same category of part covered in our hot tub wiring guide. Confirm your circuit breaker’s amperage before wiring one in — a 20A timer on a 15A breaker is a mismatch regardless of the timer’s own rating.
2. Woods 50012WD — Best Budget Pick for Inflatable Spas
Woods 50012WD Outdoor Mechanical Plug-In Timer
- Plug-in mechanical timer, 125V / 15A / 1875W — no wiring, no app, no account required.
- Weatherproof housing rated for outdoor use, with two grounded outlets.
- Up to 24 on/off cycles per day, adjustable in roughly 30-minute increments.
- Keeps its schedule mechanically — nothing to reconnect if your WiFi goes down.
This is the simplest fix for an inflatable hot tub or plug-and-play spa that runs on a standard outlet — plug the spa’s power cord into the timer, plug the timer into the wall, and set the dial. There’s no app to configure and no risk of losing your schedule if your router reboots, which is the tradeoff against the smart-plug option below. Before adding one, check your spa’s actual power draw against the 15A/1875W ceiling — most single-pump inflatable units are comfortably under that, but confirm before combining a timer with anything else on the same circuit.
3. TP-Link Kasa KP401 — Best Smart Plug for Portable Spas
TP-Link Kasa Outdoor Smart Plug (KP401)
- WiFi smart plug, 120V / 15A / 1875W, IP64 weather-resistant housing.
- App-based scheduling, remote on/off from a phone, and Alexa/Google Home/SmartThings compatibility.
- No hub required — connects directly to home WiFi.
- Same 15A ceiling as the Woods mechanical timer, so it fits the same range of inflatable-spa loads.
The KP401 does everything the Woods timer does, plus app scheduling you can adjust from your phone without walking outside to the dial, and a one-tap override if you decide to heat the spa off-schedule. The tradeoff is dependence on home WiFi and TP-Link’s app staying supported — a mechanical timer has no such failure mode. Either is a reasonable choice for an inflatable spa; pick the smart plug if you want remote control, pick the Woods timer if you’d rather not add one more app to your phone.
4. ThermoMart 40A Smart Outlet Box — Best for Hardwired 240V Spas
ThermoMart 240VAC 40A Smart WiFi Outlet Timer Box
- Purpose-built for 240V hardwired loads — rated 40A / 240VAC / 10HP with dual-hotline capability.
- UL-listed contactor, weatherproof outdoor housing, manual override switch built in.
- App-based scheduled, countdown, and loop timers; supports shared multi-user app control.
- Not interchangeable with 120V smart plugs — this is the only smart option rated for a 240V spa circuit.
Most hard-shell spas with a full-size heater run on a 240V circuit, and this is the category most buyers get dangerously wrong by grabbing a standard 120V smart plug because it’s cheaper. A 240V circuit needs a device actually rated for that voltage and amperage — this unit’s 40A/10HP rating covers a spa pump and heater load that would overload a 15A consumer smart plug immediately. If you’re not sure which voltage your spa runs on, that’s a question for the install documentation or our hot tub wiring guide before buying anything here — and if your breaker keeps tripping already, a timer won’t fix that; see our hot tub keeps tripping the breaker guide first.
How to pick the right one in three questions
- What voltage is your spa’s circuit? Check the breaker panel label or your owner’s manual. 120V and 240V devices are not interchangeable — this is the single most important spec on this page.
- Is your spa plugged into a standard outlet, or hardwired into a spa pack? Plug-and-play spas take a plug-in timer (Woods or Kasa); hardwired spas need a panel-mount or dedicated 240V unit installed in line with the circuit.
- Do you want app control, or would you rather never think about WiFi again? The mechanical options (Intermatic, Woods) never lose their schedule to a router reboot; the smart options (Kasa, ThermoMart) add remote scheduling at the cost of that dependency.
The bottom line
There’s no universal “best” hot tub timer — the right pick is whichever one matches your spa’s actual voltage and wiring, full stop. Get the Intermatic PB913N for a hardwired 120V hard-shell spa, a Woods 50012WD or Kasa KP401 for a plug-and-play inflatable, and ThermoMart’s 40A 240V unit for a hardwired 240V spa — never a standard smart plug on that last one. Still deciding what kind of spa to run a timer on in the first place? Start with our best inflatable hot tub or best plug-and-play hot tub picks, and pair whichever timer you choose with the efficiency habits in our hot tub running cost guide — insulation and a good cover still do more for your power bill than any timer alone.