Watts to kWh Calculator

The kWh figure is the one that shows up on every supplier bill, every benchmarking report and every SECR submission. Working backwards from equipment wattage and operating hours into kWh is the analytical move that lets a finance team or facilities lead say, with confidence, that the bill they received is consistent with the kit they own and the hours it runs. A 1.5kW server cabinet running 24/7 for a year consumes 13,140 kWh. At a unit rate of 28 p/kWh, that is £3,679 a year, in one cabinet, in one server room.

For multi-site portfolios, the watts to kWh conversion drives the asset audit. Walk a site, log the nameplate watts of every plug load, estimate the operating hours, and the resulting annual kWh figure tells operations where to look first. Always-on phantom loads (printers in sleep, vending machines that never get switched off, CCTV NVRs sitting idle) typically account for 10 to 20% of total consumption on commercial sites, and almost all of that is recoverable through simple scheduling or replacement.

Purely Energy turns this site-level work into portfolio-scale savings for the 2,000+ sites we manage. We use the Purely Insights platform to monitor consumption continuously, flagging sites where the baseload has crept up between contract years, and we feed those findings into the next contract negotiation so the volume forecast and the tariff shape track what the operation actually does. The result is a contract that is cheaper to buy and easier to manage than one specified against last year's bill.