How does WattLock work?

Inside the box

WattLock contains a TrueWatt circuit built around an approved, high-performance capacitor, sealed in a fire-resistant casing about the size of a phone charger.

It uses the same power-correction principle as the large cabinets fitted in factories – scaled down to plug into a home socket.

WattLock Energy Saver

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What one WattLock covers

WattLock works on the whole circuit it's plugged into – every socket on that ring, day and night. Most UK homes have more than one socket circuit, which is why bigger homes use 2–4 units.

Results vary

The effect depends on your appliances, your circuits and your tariff. Test it with your smart meter – you're covered by our 30-day money-back guarantee.

WattLock in plain English

WattLock is a plug-in device that sits on one socket and connects to the circuit that socket is wired to. Inside is a TrueWatt circuit built around an approved capacitor. Many household appliances – fridges, freezers, washing machines, pumps and motors – don't use electricity perfectly efficiently. Devices like WattLock are designed to help stabilise the supply on that circuit.

You don't need to change your appliances, rewire anything or download an app. Plug it in, switch on, and the green light confirms it's running. It's designed to stay plugged in permanently.

What affects your results

Because every home is different, we don't promise a fixed saving. The honest approach is to compare your meter or smart meter readings before and after, over a few weeks with similar weather.

• The type of appliances on each circuit (motors and compressors matter most)
• How many hours a day those appliances run
• Whether every socket circuit in your home has a WattLock
• Your tariff and unit price
• Seasonal changes in heating, lighting and usage

How to measure the difference

Write down your meter reading at the same time each day for a week, or use the daily figures on your smart meter's in-home display or supplier app. Then plug WattLock into each socket circuit and record the same readings for the next few weeks. Try to keep habits similar – the same number of washes, cooking pattern and so on – so you're comparing like with like.