One of the first decisions anyone faces when buying a Washloo is choosing the format. You've read about the features (the warm water wash, the heated seat, the dryer, the remote) and you're sold on the idea. But then you discover that there are two quite different ways of getting those features into your bathroom: a smart toilet seat that fits onto your existing toilet, or an all-in-one unit that replaces the toilet entirely.
The core experience is the same in both cases. The wash functions, the heated seat, the warm air dryer, the night light - all of it is available across both formats. What differs is the form factor, the installation, the aesthetics, the flush mechanism, and a handful of specific features that are only possible in one format or the other.
Washloo's Japanese Toilet Guide gives a good overview of what smart toilets do. This guide focuses on the format decision specifically - which type of product is right for your bathroom, your budget and your situation.
The Two Formats Explained
The Smart Toilet Seat (Bidet Seat Attachment)
A Washloo smart toilet seat — the Classic, Classic Mini R, Finesse, or Omega — fits onto your existing toilet pan in place of your current toilet seat. The pan, cistern, and plumbing stay exactly as they are. You're adding functionality to what you already have, not replacing it.
The seat connects to the existing water supply via a T-piece connector on the inlet hose, and to a power supply via a fused spur or the unit's RCD-protected plug. The whole installation can be completed in an hour or two, and in most cases the plumbing element requires no tradesperson — just a competent DIYer comfortable with basic plumbing. The electrical element typically requires a Part P registered electrician to install a fused spur if one isn't already present.
The flush remains conventional — the existing cistern fills and empties as it always did. The smart seat adds wash, dry, heat and controls on top of that, without changing the fundamental plumbing of the toilet.
The All-in-One Smart Toilet
A Washloo all-in-one smart toilet (the Prestige, Evolutio, or Supreme) is a complete replacement for the entire toilet. The existing pan, cistern and seat all come out. The new unit goes in: a single, cisternless toilet basin with all smart functions built directly into the unit itself.
The all-in-one units are cisternless, using an internal tank and an ultra-quiet pump for a jet flush. At just 58cm long, the Prestige is notably compact — neater than most standard toilets on the market. The Supreme adds a Foam Shield function that prevents splashback and isolates odours at the source, along with a UV light that helps kill bacteria in the pan.
Flushing on the all-in-one units is largely automatic. The Prestige detects when the user stands up and flushes automatically. A manual flush can be operated via a foot button on the front of the unit, and a battery backup ensures flushing works even during a power cut.
Installation requires a plumber and electrician — water, waste and power all need to be connected to the new unit. It's a more involved job than fitting a bidet seat, though not a major bathroom renovation.
What They Have in Common
Both formats deliver the core Washloo experience: rear and front wash, adjustable water temperature and pressure, oscillating spray, warm air dryer, heated seat, night light, auto deodoriser, seat sensor, One Solution auto cycle, and the wireless remote. The fundamental reason most people buy a Washloo (hands-free cleansing that replaces toilet paper) is available equally in both formats.
Both also carry Washloo's market-leading 15-year ceramic warranty and 24-month comprehensive electrical warranty, with in-house technicians who typically resolve issues within five days. The warranty terms don't distinguish between seat and all-in-one — both are backed to the same standard.
Where They Genuinely Differ
Installation Complexity
This is the most practical difference for most buyers.
A bidet seat can be fitted to most UK toilets in an hour or two, with the plumbing element manageable as a DIY job and only the electrical connection requiring a tradesperson. You're not changing the toilet; you're adding to it.
An all-in-one requires the removal of the existing toilet and the installation of a new unit, including new waste and supply connections. This is a professional installation job. It's not complicated in the sense of requiring major building work, but it isn't something most people would tackle themselves, and it should be factored into the overall cost and timeline.
The Flush Mechanism
Standard toilets (and toilets paired with a bidet seat) use a gravity-fed cistern flush. Water fills the cistern from the top, and releasing the flush valve lets gravity do the work. It's simple, reliable and doesn't require power to operate.
All-in-one Washloo units use a pumped jet flush from an internal tank. These units use just 2.5 litres of water per flush, roughly half that of a standard toilet. The flush is powerful, quiet, and significantly more water-efficient than a conventional system. The trade-off is that the primary flush mechanism requires power. The battery backup covers this for power cuts, but it's worth knowing that the flush experience is fundamentally different from a cistern — it's faster, more forceful and uses less water.
For most people, the pumped flush is an improvement. For anyone used to the reassuring simplicity of a gravity cistern, or who has concerns about power dependency, it's worth thinking about before committing.
Auto-Opening Lid and Foot Sensor
The Supreme takes hands-free operation to its logical conclusion. A foot sensor at the base of the unit detects a wave of the foot and opens the lid automatically. A second wave raises the seat. A third closes both. The entire approach to the toilet, from opening the lid to closing it after use, requires no hand contact whatsoever.
This feature is only available on the all-in-one Supreme; it's not possible on a bidet seat, because the lid and seat mechanism on a standard toilet doesn't have the same integrated electronics. For people with very limited hand function, the foot sensor is a genuinely significant accessibility feature.
The Foam Shield and UV Light
The Supreme also includes two features that aren't available on any bidet seat: a Foam Shield that prevents splashback by coating the pan in a layer of foam before use, and a UV light that helps sanitise the pan between uses. Both are built into the unit itself and operate automatically.
Again, these are only possible in an all-in-one configuration. There's no way to retrofit them to a bidet seat, because they're integrated into the pan and the unit's electronics.
Aesthetics and Form
A bidet seat fitted to an existing toilet looks like a toilet with a slightly thicker seat. The cistern and pan remain as they are, so if the existing toilet is older, not particularly attractive, or simply not the right height, the bidet seat doesn't change any of that. It improves the toilet experience without changing its appearance.
An all-in-one smart toilet is a complete contemporary bathroom fixture. Cisternless, compact, and designed as a unified product rather than a combination of components, it has a cleaner, more intentional appearance. In a bathroom that's been recently renovated, or where aesthetics genuinely matter, the visual difference between the two approaches is noticeable.
Compatibility With Existing Toilets
Washloo bidet seats are compatible with V-shaped and D-shaped toilet pans, covering approximately 98% of UK toilets. If your existing toilet is within that range and has adequate clearance behind the seat, a bidet seat will fit.
All-in-one units replace the toilet entirely, so compatibility isn't a question — the new unit has its own pan, and it connects to standard UK waste and supply configurations. You do need to check the waste pipe orientation: the Supreme uses a P-trap (horizontal waste exit); if you need an S-trap (vertical waste exit), you'd need to look at the first-generation Prestige or Supreme models. A plumber can confirm which applies to your bathroom.
The Smart Toilet Combination: A Middle Ground
Washloo also offers a third option, smart toilet combinations, which sit between the two formats. These pair a Washloo bidet toilet seat with a brand-new rimless toilet pan, supplied together as a matched set. You get a new, modern pan and a smart seat as a complete package, without going to the full all-in-one unit.
This is a useful option for people whose existing toilet pan is old, incompatible, or simply not the right height but who don't need or want the full cisternless all-in-one experience. The flush remains conventional; it's the pan and seat that are new.
Which Format Is Right for You?
Here's a straightforward way to think through the decision.
Choose a bidet toilet seat if your existing toilet pan is compatible, your bathroom doesn't need a full overhaul, you want to minimise installation complexity and cost, and you're happy with the conventional cistern flush. The Classic is a practical entry point; the Finesse is the premium seat option.
Choose an all-in-one smart toilet if you're renovating your bathroom and want a complete, contemporary installation; you want the water efficiency of a 2.5 litre pumped flush; you want the auto-opening lid and foot sensor of the Supreme; or you want the cleanest possible integrated appearance. The Prestige is the entry point to this format; the Supreme is the fully specified model.
Choose a smart toilet combination if your existing pan is old or unsuitable, you want a fresh matched pan and seat together, but a conventional cistern flush is fine and you don't need the cisternless all-in-one format.
Frequently Asked Questions
Can I get the same wash quality from a bidet seat as from an all-in-one? Yes. The core wash and dry functions (rear wash, front wash, oscillating spray, adjustable temperature and pressure, warm air dry, heated seat) are available across both formats. The all-in-one Supreme adds Foam Shield and UV light, which are exclusive to that unit, but the fundamental wash experience is the same.
Does the all-in-one need a plumber to install? Yes. Removing the existing toilet and connecting a new unit to the waste and supply pipes is a job for a competent plumber. The electrical connection also requires a Part P registered electrician.
What happens if the power goes out with an all-in-one? The battery backup on Washloo all-in-one units maintains the flush function during a power cut. The wash and dry functions require power and won't operate without it.
Is the all-in-one suitable for a bathroom with limited floor space? The Prestige, at 58cm long, is more compact than most standard close-coupled toilets. The cisternless design also eliminates the space taken up by a conventional cistern. For smaller bathrooms, the all-in-one can actually be more space-efficient than a standard toilet with a bidet seat.
Can I use 0% finance on either format? Yes. Washloo's 0% finance option through DivideBuy is available across the range. See the product page for current terms.
Which model is best for accessibility needs? All Washloo products have accessibility benefits. For people who need hands-free operation, the Supreme's foot sensor makes it the most fully hands-free option. For people who need a height-adjustable toilet as well as smart functions, the Washloo Levitate — available through Wash-Able — combines a rise and fall mechanism with a Washloo smart toilet pan.