Tewke rebuilt the light switch as a bootstrapped energy-control device (interview)

Tewke is a London climate-tech and smart-home company selling Tap, a wall switch with sensors and AI for lighting, energy management and environmental sensing.

The light switch, understood by everyone, is the interface that can scale household energy control; keep physical buttons so the lights work if software fails.

In the Tech.eu feature, Piers Daniell, who founded Fluidata (now FluidOne) in 2006 and exited in 2019, says he saw the grid pay his data centres to go offline and wanted demand control in homes. He recruited Rowan Dixon, then studying design engineering at Imperial while working in Microsoft R&D, to build it from a 'napkin sketch'.

Tap has three layers: a frame, a wired core replacing the switch and a magnetic display module with sensors and compute. The founders say each unit carries nine sensors and that they patented a way to power the electronics with or without a neutral wire, needed because many European homes lack neutrals at the switch. They manufacture in the UK, do electronics, mechanics, design, software and AI in-house, and added TewkeAI, an embedded voice interface.

Daniell says demand-side control at home level was unsolved while grids pay for flexibility

A light switch is universal, usable by children, grandparents and visitors, unlike complex automation systems

Controlling the switch and the socket, the founders say, means controlling most energy use in a home

Selling through electricians gives installation, education and a sales channel in one

Choosing a familiar object as the interface solves usability first and energy savings second; the founders say bootstrapping forced discipline, but the claims are theirs.

As of 28 January 2026 Tewke was an early hardware company with about 16 staff and no disclosed sales or revenue figures. The founders describe a long-term vision of positioning the home within the smart grid and being seen as a software and energy-intelligence company.