Coway Bidetmega 400S vs Coway Bidetmega 500S
| Spec | Coway Bidetmega 400S | Coway Bidetmega 500S |
|---|---|---|
| Price | $449 | $449 |
| Rating | 4.5★ (250) | 3.7★ (70) |
| Type | Electric Bidet Seat | Electric Bidet Seat |
| Water Heating | Tankless (Instant Heat) | Tankless (Instant Heat) |
| Controls | Wireless Remote | Wireless Remote |
| Toilet Fit | Elongated & Round versions | Elongated & Round versions |
| Power | 120V GFCI outlet; short cord | Needs GFCI outlet within reach |
| Spray Pressure | Adjustable pressure + Turbo mode | Adjustable pressure + Turbo, i-wave 3-stage |
| Nozzle | Stainless nozzle with UV + mist shield | Stainless wand + UV light & WaterShield mist |
| Install | 30-45 min DIY | under 30 min DIY |
| Warm water | Yes | Yes |
| Heated seat | Yes | Yes |
| Warm air dryer | Yes | Yes |
| Wireless remote | Yes | Yes |
| Night light | Yes | Yes |
| Deodorizer | No | Yes |
| Self-cleaning nozzle | Yes | Yes |
| Feminine wash | Yes | Yes |
| Warranty | 1-year limited | 1-year limited |
Pros & cons
Coway Bidetmega 400S
- ✓i-wave course washes are the standout: one button runs a 3-stage cycle that steps through pressure, temperature, and nozzle motion — closest thing to 'set and forget' in this price class
- ✓New-for-400S instant heating ends the original 400's warm-water limits, and a dedicated child mode makes it a favorite for family bathrooms
- ✓WaterShield mist pre-wets the bowl before you go — the same anti-stick trick as Toto's premist, which the Alpha JX only recently copied
- ✓UV light plus auto-rinse keeps the stainless nozzle sanitized between uses, a hygiene stack usually found on $700+ seats
- ✓Two user-preset buttons sit right on the remote (User 1 / User 2), so couples aren't re-dialing settings every visit
- ✓The flat, sculpted lid won a 2024 PIN UP Design Award — repeatedly called the best-looking seat this side of a Toto S550e
- ✓A Gadgeteer reviewer reported zero complaints after 6 months and noted it matches competitors' features 'for $100 less'
- ✓Home Depot reviewers describe the default spray as 'just right' — firm but never harsh, ideal for sensitive skin and first-timers
- ✗The warm-air dryer is the most-cited weakness — reviewers say it's underpowered and most still finish with a pat of paper
- ✗The power cord is notably short; multiple owners had to buy an extension cord to reach their outlet
- ✗No deodorizer, which the similarly-priced Toto C5 includes
- ✗Turbo mode aside, peak pressure is tuned gentle — spray-strength chasers coming from a Bio Bidet vortex wash will be underwhelmed
- ✗Only a 1-year warranty against Alpha's 3 years and the Discovery DLS's 5 — thin coverage for a $450 electronics purchase
- ✗The seat body is bulkier front-to-back than it photographs, and some owners mention losing sitting room
- ✗The 400S launched in 2025, so there's no long-term reliability record yet — and original 400 owners report its parts are drying up post-discontinuation
- ✗Coway's direct price is $599 while Amazon sells it near $450; the retailer spread makes it easy to overpay
Coway Bidetmega 500S
- ✓Motorized lid opens as you approach and closes quietly after - the only seat in Coway's lineup with it, and it undercuts Toto's auto-lid S7A by hundreds
- ✓UV light sterilizes the nozzle between uses, a genuine hygiene step beyond the self-rinse most seats call cleaning
- ✓WaterShield fine mist coats the bowl to keep waste from sticking, like Toto's PreMist but included at a lower street price
- ✓Instantaneous heating delivers unlimited warm water with i-wave's 3-stage adaptive wash
- ✓Integrated deodorizer plus night light round out a true flagship feature list - nothing is optional
- ✓Sells for $400-500 regularly (nearly 40% off its $699 list), making it cheaper than the Bidetmega 400S was at launch
- ✓Available in both elongated and round, unlike the elongated-only 200N
- ✓Under-30-minute install despite the motorized hardware - reviewers found setup surprisingly simple
- ✗3.7-star Amazon average is a red flag - the motorized lid and electronics generate far more complaints than simpler seats
- ✗Auto-lid troubleshooting is common enough that Coway support runs a dedicated help channel for it
- ✗More motors and sensors mean more failure points, backed by only a 1-year warranty - a third of the Alpha UX Pearl's coverage
- ✗At $699 list it's poor value; only buy at the frequent sub-$500 street price
- ✗Motorized lid isn't sittable and adds bulk versus Alpha's low-profile seats
- ✗The auto-lid can open for pets or passersby, which owners find gimmicky in small bathrooms
- ✗Remote is Bluetooth-dependent; pairing hiccups lock you out of lid control
- ✗The 400S at $449 delivers the same core wash quality if you can live without the lid theatrics