Coway Bidetmega 400S review – You’ll never want to “go” anywhere but home

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Coway Bidetmega 400S 14

REVIEW – When we travel, my wife and I miss our gadget-populated home, especially our bidet. No, I’m not kidding. Once you’ve used one like the Coway Bidetmega 400S, riding the porcelain express anywhere else just stinks  (pun intended) :-).

⬇︎ Jump to summary (pros/cons)
Price: $448.00
Where to buy: Coway, Amazon



What is it?

The Bidetmega 400S is a remote-controlled, electric appliance that combines a heated toilet seat, water heater, and warmed air dryer for cleansing after bathroom activities.

What’s included?

  • 400S bidet toilet seat
  • Bidet hose
  • Water hose adaptor tee
  • Mounting bracket
  • Mounting bracket slides (2)
  • Mounting bracket bolts (2)
  • Mounting bracket bolts, positioning washers, and inserts
  • Remote control with three AAA batteries
  • Remote control wall bracket
  • Screws and drywall anchors
  • Remote control stand and two screws
  • 3M double-sided tape for remote control mounting
  • User manual

Tech specs

  • Model: 400S
  • Rated voltage: 120V, 60Hz
  • Power consumption: 1450W
  • Power cord, 1.5m (59 in.)
  • Water supply pressure: 0.11 to 0.68MPa (16 to 98.6 PSI)
  • Product size: Elongated – 390 x 532 x 134mm, Round – 390 x 497 x 134mm
  • Product weight: Elongated – 3.9kg (8 lbs. 10 oz), Round – 3.8kg (8 lbs. 6 oz)
  • Max flow: 0.60L/min, Nozzle self-washing function
  • Rated cleaning time: 2 minutes for cleaning, 2 minutes for bidet
  • Water pressure control: Mycom control, five levels
  • Water warming setting: 4 levels – off: room temperature, weak: 30-40°C (86 to 104°F)
  • Water drying power: 1400W max.
  • Air drying: 4 levels
  • Air drying time: 2 minutes
  • Air drying power consumption: 180W
  • Safety devices: Bimetal thermal overload, Thermal fuse, relay
  • Heated seat: 4 levels
  • off: room temperature
  • low: 31°C (87.8°F)
  • medium: 34°C (93.2°F)
  • high: 37°C (98.6°F)
  • Soft open and close
  • Two-user memory settings
  • Mesh filter
  • “Mood” LED
  • Toilet LED
  • Power saving mode

Design and features

I reviewed Coway’s Bidetmega 150 (read it here) back in January 2021 and have been using it every day since. My wife and I were recently discussing how much we value it and considering installing a second bidet in our other bathroom, so I was elated when the Bidetmega 400S arrived.

The box is bulky, but it’s not particularly heavy at under 9 pounds.

Coway Bidetmega 400S 01




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The seat is completely assembled and requires a nearby electrical socket—the electrical cord routes through either the left or right side. A great design.

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Of course, removing the old toilet seat will be necessary. Please do yourself a favor – turn off the water, flush, drain the tank, and have a few paper towels handy for the few drips that will inevitably make it to the bathroom floor.

The 400S attaches to the toilet in minutes using a clever bracket system. Two rubber nuts (they’re internally threaded) push through the mounting holes. They’re a tight fit, but are exceptionally stable. Well done, Coway.

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A plate straddles the mounting nuts and is adjustable from front to back. Two toothed plates fit into the mounting plate and are laterally adjustable. Toothed square nuts nest into the lateral plates, and bolts tie the assembly together. Nuts screw onto the bolts and tighten the seat. The entire process took only minutes and required a screwdriver and an adjustable wrench.

Coway Bidetmega 400S 12

Next, install the tee and hose. In my case, I used the existing fitting. I appreciate the stainless steel hose and high-quality parts. Everything tightened in place with no leaks on the first try.

The seat slides towards the tank and clicks into place. Tadaa!




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To release the seat for cleaning, press the button on the side and slide it forward. Because there’s lots of water splashing during use, some… stuff… can work its way under the seat around the mounting bracket. You’ll want to add this job to your regular cleaning chores so it doesn’t get… funky.

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A detector in the seat prevents operation unless the seat is occupied.

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There’s a power LED and buttons on the side for frequently used functions: “Power”, “Light”, “Nozzle Clean”, and “Rear.” It didn’t take much practice to memorize the locations, but for most use, the remote control works best.

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The Remote control is an interesting beastie with buttons on both sides. It feeds on three AAA batteries. I was surprised to find that Coway uses Duracell rather than some off-brand product.

Buttons on the back control “Move” (shifts the nozzle back and forth for wider cleaning), “Air+” aerates the water stream, “Wide” (changes the spray pattern), “Seat Temp.,” and “Water/Dry Temp.”

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The “front” of the remote sports, “Stop,” “Rear” (starts the water stream towards the back), “Front” (aims towards the front), “Turbo” (pulsates the water stream), “Dry” (starts the air dryer), Pressure and Position, and two User setting buttons.

By default, “User 1″ is preconfigured for children; however, both buttons are programmable to accommodate preferred configurations. A great feature! My wife is 4’9″ and I’m 5’6” and have different inclinations when we use the 400S.

Coway Bidetmega 400S 09

There are several “special functions” accessible by simultaneously pressing the “Stop” and “Rear” buttons for three seconds. Sound, Seat Detection, Power Saving, and Water Shield (an interesting mode that sprays the inside of the bowl to help reduce “contamination”)

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3M double-sided tape secures the remote base to a convenient location. If you prefer, Coway also supplies a tabletop base and screws.

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The water nozzle extends from these ports.

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No, bathroom habits aren’t a typical topic of discussion in my home, but my wife and I both LOVE the Bidetmega 400S!

Final thoughts

My first experience with a bidet was in the ’90s in Japan. Since then, I’ve traveled extensively throughout Europe and often wondered why bidets never caught on in the USA. Seriously, they are lovely things. Since installing one in 2021, I’ve found that having one cuts my toilet paper usage and makes me feel “shower-clean” every time I use it. It installs as easily as a conventional toilet seat, is easy to operate, and performs excellently. I can’t tell you how much I love the Bidetmega 400S! Brilliant Job, and thank you, Coway!

What I like about the Coway Bidetmega 400S

  • Simple installation with just a few tools
  • Adjustable seat, water, and drying temperatures
  • Adjustable positioning and water pressure
  • A fantastic bathroom experience every time!

What needs to be improved?

  • A backlit remote would be cool for middle-of-the-night bathroom visits

Price: $448.00
Where to buy: Coway, Amazon
Source: Coway provided a free sample for this review but did not provide input, guidance, or editing before publication.

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