WattStack

One app for all your energy devices. No guesswork.

WattStack puts you in control of your hot water cylinder — and soon your heat pump, battery, and EV charger too. See exactly what your energy is costing you, shift usage to cheaper tariff windows, and never run out of hot water again.

See what matters
Real-time temperature and power monitoring. History charts from the last hour to the last week. Energy costs broken down by tariff band so you know exactly where your money goes.

Heat on your terms
Four behaviour modes — Savings, Balanced, Comfort, and Schedule — let you choose how your device runs. Need hot water now? Tap Boost. Heading away? Tap Away. It is that simple.

Save on every bill
WattStack understands your tariff. If you are on Octopus Agile, Economy 7, or any time-of-use plan, it finds the cheapest heating windows automatically. Stop heating at peak prices without thinking about it.

Earn from the grid
Grid flexibility services pay your devices to adjust demand during peak periods. WattStack handles enrollment, scheduling, and earnings — you just opt in.

Premium unlocks more
Unlimited schedules, 5-year history, up to 5 household members, ad-free experience, and lower flex commission. £3/month.

WattStack works with any device powered by WattStack Edge — the open-standards board that makes energy hardware intelligent and grid-connected.