Toto S550e vs K300: Is It Really Worth Spending More?

By Veronica Fletcher | 
Last updated on April 3, 2021

These reviews are based on my own research and testing, and are intended to help you find the best products. If you purchase through this page, I may earn a commission at no extra cost to you. Learn more.

The Toto K300 and S550e are two of the best washlets bidets from the Toto range.

But is the S550e worth the extra money?

Only you can decide that, but I can give you all the knowledge you need to make an informed decision. (Hint: I’d go for the s550e)

Here’s a quick summary of the differences between the Toto S550e and the Toto K300. 

The S550e uses ewater+, has a nightlight, an automatic opening and closing lid, and two extra spray modes. The K300 lacks these features,  but both have air deodorizers, a powerful dryer, remote controls with the ability to remember user settings, and tankless heating with unlimited hot water.

In a rush? Click here to view the Toto K300 and here to view the Toto S550e (both open in new tabs).

What’s the same?

You can expect the standard features with both bidets, such as a heated seat, self-cleaning wands, and adjustable temperature and pressure. 

These are pretty self-explanatory. I won’t bore you with the details. 

But there are some cool features both bidets share that I wanted to talk more about.

To skip to the differences click here, or just keep scrolling.

  • Air deodorizer. Do you dread someone wanting to use the toilet after you? Or do you avoid the bathroom for a few minutes (or an hour) after a certain someone has used it? No more. Toto’s carbon-filter air deodorizer automatically filters the air around your toilet, INSTANTLY removing foul odors. 
  • Illuminated remote control with user settings. 
K330 vs S550E remote
  • It’s not ideal having to adjust settings every time you use something. So it’s a good thing that with these bidets you don’t have to! The remote can remember up to two different user preferences for water temperature, pressure, and wand position. Both washlets also come with a docking station for the remote.
  • Air dryer.  The dryer on both models is one of the STRONGEST on the market. It has an airflow of 10.24 ft3/min, and you can pick from three different temperature settings. No need to use scratchy and irritating toilet paper.
  • Instant water system. The bidets heat water on demand, rather than holding it in a tank. This means you have UNLIMITED hot water and a much slimmer seat. It also saves energy because you’re not continually heating water.
  • Energy save mode. Another way to save energy is to engage energy-saving mode. You can lower the temperature of the seat or turn it off completely. And you can either set the bidet to detect periods of low usage itself (clever, right?), or you can pick when to turn it on. Who doesn’t like saving the planet!


I left premist for last because it’s unique to TOTO washlets, so you might not have come across it before.

The concept is simple. 

Think of it like greasing a pan before you fry an egg. You don’t want the egg to stick, so you coat the pan with some oil.

You don’t want any dirt sticking to your toilet bowl, so the bidet coats it with a thin film of water.

The water acts like oil and stops any dirt from adhering.

What does this mean for you?

You’ll no longer have to scrub any skid marks off the toilet! 

What’s different?

The way Toto works is that the more expensive models have everything the cheaper models have, plus a few extra features. 

The S550E is the king of the toto bidet seats. It has the most features in the range (and possibly of any bidet ever!). 

Big claim, I know. But justified. 

I’ve gone through each feature the S550E (amazon link) has that the K300 (amazon link) doesn’t. Read through them and you can decide if these extra features are worth the extra dollar. 

I say it is.


As a self-confessed clean freak, this one really excites me. 

Ewater = electrolyzed water 

The water from your mains is turned into Ewater as it passes through the bidet. 

It’s used to: 

  • Mist your toilet bowl after use to get rid of any unseen dirt and bacteria
  • Clean the spray wands
  • Clean your toilet bowl after 8 hours on non-use

Ewater will leave your toilet bowl 80% cleaner than normal. 

Watch the video below for a demonstration.

The water is a proven disinfectant and means you rarely have to clean the toilet yourself. This cuts down on the need to buy and use hard chemical cleaners.

The water is completely non-toxic. It’s even safe to drink… not that I recommend drinking from your toilet.

It’s good for the environment and saves you time AND money.

Automatic open and close lid

Imagine this.

You walk up to your toilet, and it welcomes you by automatically opening up the lid.

Then, when you’re done, the lid slowly closes as you walk away.

The height of luxury. You can have this with the S550E.

For the men reading this, there’s also a button on the remote that will automatically lift the seat and put it back down again.

This creates a totally hands-free experience (and means the women in your house will stop moaning at you for leaving the seat up).

Can life get much better?


Okay, now imagine it’s nighttime. 

Your bathroom is pitch black, but you need the toilet.

With a regular, boring toilet, you blind yourself turning on the main light and stumble back to bed wide awake.

Going to the toilet at night doesn’t have to be like that.

With the Toto S550E, a soft light illuminates the toilet. This means there’s no need to turn on the main light and you can return to your bed still half asleep.


Spray modes

The s550e offers more spray modes than the K300.

BidetRear cleansingRear soft cleansingFront cleansingWide front cleansingOscillating cleansingPulsating cleansing

The two extra spray modes are the wide front cleanse and the pulsating spray.

The wide front cleanse is very useful for women and gives a fuller coverage clean. Perfect for using on your period or even during the postpartum stage.

The pulsating spray has a massaging effect. It’s great for getting rid of stubborn bits of dirt. 

On demand wand cleaning

Most bidets these days come with self-cleaning wands. The K300 and the S550E are no exception.

But what’s not so common is being able to clean the wand whenever you want. 

The S550E has a button on the remote for exactly that.

As soon as you notice any dirt building up, you can rinse the wand to get rid of it. This decreases how often you need to do any cleaning.

Final Thoughts

Both are solid choices, and you won’t be disappointed with either.

The K300 is one of Toto’s newest offering and the S550E is Toto’s top of the range model. 

Who should buy the Toto K300?

If you’re trying to keep the costs down then go for the K300. 

It’s a fantastic, modern bidet that will get the job done quickly and effectively plus it comes with several luxury features. Some of which you won’t find elsewhere. 

Who should buy the Toto S550E?

If you want the WOW factor and ultimate luxury go for the S550E.

You’re getting the best bidet money can buy. There’s no feature it doesn’t have. 

Going to the toilet will be an experience rather than something you have to do. 

Warning: your toilet usage may increase!

About Veronica Fletcher

Veronica has a passion for all things eco-friendly. After growing up on a farm in Ireland, she went on to study Chemistry and Environmental Sciences. Veronica has also volunteered in many sustainability roles, including conservation efforts in Bangladesh and teaching Environmental Sciences to schoolchildren in Kenya.