Toilet seat up or down? The solution might be mechanical engineering

27 June 2023

Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.

The age-old debate rages: should you leave the toilet seat up or down?

Closing the seat, as well as the lid, is more hygienic. But in public toilets, leaving seats down can mean that people don’t bother to put them up when they need to, making things messier.

Manufacturers do sell seats with electronic sensors that can raise or lower seats automatically, but such designs are expensive.

While not the most pressing conundrum of the age, this problem did capture the attention of a group of engineering students at Boston University and Massachusetts Institute of Technology.

They’ve now developed a pair of toilet seats that raise and lower automatically with mechanical pressure.

“When someone is sitting on the seat, they apply pressure and our mechanism can automatically detect when the user is finished,” says Andy Chang, co-founder and chief financial officer of Cleana, the company they’ve spun out of their seat design.

“After a set amount of time, the seat will then auto-lift (in commercial settings) or lower (in residential settings).”

The seats can also be raised or lowered by hand without affecting the mechanism – so users can raise or lower the seat by hand before use.

Chang says the seats took four years of work to develop.

“To ensure our product would meet the needs of its users, we undertook comprehensive surveys involving over 1500 facility and custodial staff members and several thousand residential users.

“We discovered that the main reason why bidets or self-cleaning seats aren’t being implemented in public areas is that many facility managers find battery maintenance labour-intensive and expensive.”

They focussed on finding a pneumatic system that could be powered by someone raising or lowering the seat initially, rather than using an external source of power.

“We focused on designing toilet seats that prevent mess using a fully mechanical system, alleviating the need for battery maintenance,” says Chang.

So that’s why the seats raise themselves in public – why do the seats designed for private bathrooms go the opposite way?

“While at home, the auto-closing lid will also help address several other problems in the bathroom including bacteria spread from toilet spray, pets and young children accessing open toilet bowls, folks dropping items in the toilet, or relationship issues – having to tell the men always to lower the seat after usage,” says Chang.

Originally published by Cosmos as Toilet seat up or down? The solution might be mechanical engineering

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