TOTO's Flagship Washlet Bidet Seats: S500e/S550e vs. S7/S7A

While the S500e and S550e were TOTO's flagship Washlet models for the last half a decade, in 2023, TOTO introduced the S7 (replacing the S500e) and the S7A (replacing the S550e) as their new top-of-the-line options for bidet seats. 

Right away we'll note that the only difference between S7 and S7A is that the S7A includes an automatic open/close seat and lid, whereas the S7 does not. 

Below we'll discuss the differences between this new generation and the previous flagship editions.

• The S7/S7A have a thinner profile with the rear seat height of ~4.1", down from 4.5 - 5" on the S500e/S550e. 
• They are also lighter, with the S7/S7A weighing 15 lb, compared to 16 lb for the older models.
• The S-models come with two distinct lid designs: Contemporary (smooth rounded) or Classic (beveled), both offering a seamless seat design eliminates the dirt trap under the hinge that existed in earlier models. 
• S7/S7A come with a horizontal remote featuring larger, tactile buttons—an upgrade from the capacitive touch remotes on S500e/S550e. This also means that the battery lasts longer since the remote has no display screen on the back .
• The new models feature four user presets (up from two), so each household member can save settings for seat/temp/dryer/water pressure.
• The new "back-side" fine-tuning buttons allow adjustments not previously accessible. 
  Another innovation is that the EWATER (electrolyzed cleaning water) now rinses under the seat, not just wand and bowl.
• The PREMIST feature remains—automatically moistens the bowl on approach—but now includes under-seat mist.
• While both generations include automatic air deodorizer and adjustable warm-air dryer, the new Power Deodorizer mode intensifies the fan for extra odor control.
• Unlimited, tankless instant warm water remains standard on all four models—S500e, S550e, S7, and S7A.
• S7A and S550e include automatic open/close lid; S7 and S500e do not.
• S7/S7A retain auto-flush functionality when connected to compatible TOTO toilets (and paired with the appropriate auto flush kit that is sold separately).
• S7A can close its lid automatically before flushing—customizable via remote settings.
• All models except the original S500e include built-in night light. 
• All fit elongated bowls; S7/S7A also available in a round model.
• Installation space requirement: S7/S7A need a minimum of 2" clearance from tank to mounting holes (vs. 1¾" on older units).
• Wiring repositioned on S7/S7A to support both standard and Washlet+ installations—visually cleaner setup. 

Should You Upgrade?

Upgrade makes sense if you want:

• Sleeker, lighter profile & easier cleaning.
• Seamless seat with advanced hygiene (EWATER under seat, PREMIST).
• More customization (4 user presets, power deodorizer).
• S7A's automatic lid and programmable flush lid close.
• Extended 2‑year warranty.

Stick with S500e/S550e if:

• You're satisfied with current performance and comfort.
• Don't need extended warranty or extra remotes/buttons.
• Upgrade value isn't justified for your needs—S550e still highly capable

In short: 

• Stick with S500e/S550e if you value simplicity, comfort, and already own one.

• Move to S7 if you want all upgrades except the auto-lid feature.

• Go for S7A if you want the full flagship experience—from sleek aesthetics to hands-free convenience.

We hope this guide helps you make a more informed decision when choosing between TOTO's latest and previous-generation Washlets. Whether you're upgrading or buying your first bidet seat, understanding the real-world differences between these models can ensure you get the features that truly matter to you.