Three questions settle it, and only the third is about the product. Is there a socket beside the toilet; do the seat measurements match your pan; and where does the water connect.
1. Electricity
Non-electric seats tee off the cold supply and use line pressure — no socket, water at supply temperature. Electric seats heat water and often the seat, and need a permanent supply within reach in a damp room, which is regulated work where you live. If there is no socket, the shortlist is non-electric.
2. The three seat measurements
Exactly as for an ordinary seat: hinge hole spacing, length from the hinge holes to the front of the pan, and width. A bidet seat is a seat first, and it is returned for the same reasons.
3. The water connection
A tee at the cistern’s angle valve, usually 3/8 or 1/2 inch, with a small hose to the seat. Manufacturers supply the tee; what varies is whether your existing valve has room for it, which is why fitting a double-outlet angle valve at the same time is often the tidy answer.
What separates models beyond that
Nozzle count and whether it is adjustable, self-cleaning of the nozzle, and — on electric models — whether the water and the seat are heated or only one of them.
Questions people actually ask
Do non-electric seats work well?
They do what they are: line pressure, supply temperature. In a cold house in winter that is genuinely cold, and it is the single most common complaint. Models that tee off both hot and cold and mix exist, and that is the specification to look for.
Will a bidet seat fit any toilet?
Any pan whose measurements match, which is most standard European pans. Fully shrouded and unusually shaped pans are where they do not, and the maker publishes a compatibility range.
Last reviewed 5 September 2026