How does a Quooker tap work?

A Quooker tap looks like an ordinary mixer, but under the worktop it's a small, sealed pressure system that keeps a few litres of water permanently at 110 °C and releases it at exactly 100 °C when you press the handle. This guide explains exactly how it works — the reservoir, the vacuum insulation, the safety mechanics of the tap, and how the CUBE adds chilled and sparkling water on the same line.

The vacuum-insulated reservoir

The heart of every Quooker is a small stainless-steel tank under your sink — typically 3 or 7 litres, depending on whether you choose a PRO3, COMBI or COMBI+ reservoir. The tank holds water at roughly 110 °C, kept under pressure so it cannot boil inside the vessel.

Around that inner tank is a second outer wall. The space between the two walls is a near-perfect vacuum — the same principle a thermos flask uses. With almost no air molecules between the walls, heat has nothing to travel through. The result is that the reservoir loses only about 10 watts of heat, comparable to a single LED bulb. That's why a Quooker can sit on standby 24/7 and still use less energy per day than boiling a full kettle a few times.

Why the water stays liquid at 110 °C

Pure water at sea level boils at 100 °C — but only at normal atmospheric pressure. Inside the sealed Quooker tank the water is held under modest pressure, which raises its boiling point above 110 °C. The water is therefore very hot but never actually boils inside the reservoir, so there's no steam build-up and no kettling noise.

The moment you open the tap, the pressure drops to atmospheric. The water that leaves the spout is instantly at 100 °C and turns into the familiar fine, churning spray that's characteristic of a Quooker.

The patented child-safe tap handle

A Quooker tap isn't a normal mixer — the boiling-water channel uses a separate, double-action control. To dispense 100 °C water you have to push the ring down and turn it in a single motion. Let go and the spring-loaded mechanism cuts the flow immediately. A small LED ring on the tap signals when boiling water is active.

The spray itself is also engineered for safety: the aerator splits the stream into a soft, low-velocity cone that loses heat to the air the moment it leaves the spout, dramatically reducing the risk of scalding compared with a kettle pour.

What happens when you press the tap

1. You push and turn the boiling-water ring; the valve opens.
2. Cold mains water enters the bottom of the reservoir under pressure.
3. That cold water displaces the same volume of 110 °C water at the top of the tank up through an insulated riser tube to the spout.
4. As the water leaves the pressurised tank it drops to atmospheric pressure and exits the aerator at 100 °C.
5. The new cold water in the tank is reheated by an internal element back to 110 °C in a few minutes.

Boiling, hot, mixed: how COMBI and COMBI+ differ

• PRO3 — 3 L boiling water only. The tap's mixer side uses your normal hot-water supply.
• COMBI — 3 L boiling + 7 L of regular hot water for the Quooker tap itself, so you don't need an under-sink boiler for the Quooker side.
• COMBI+ — same as COMBI but also feeds hot water to a second kitchen mixer or appliance line, replacing an under-sink water heater entirely.

The CUBE: chilled and sparkling on the same tap

The Quooker CUBE is an optional second unit, mounted next to the reservoir. It turns any Quooker into a 5-in-1 tap that also dispenses chilled filtered water and sparkling water through the same spout — using a second dedicated channel in the tap with its own control ring.

Inside the CUBE there are three things working together:

• A carbon block filter removes chlorine, microplastics and taste impurities from the mains supply.
• A small refrigeration unit chills the filtered water to roughly 7 °C in a 1 L holding tank, ready to dispense on demand.
• A food-grade CO₂ cylinder (425 g) injects carbonation just before the water leaves the tap, giving you sparkling water at the freshness of a freshly-opened bottle. One cylinder typically lasts 60 L of sparkling water — enough for an average household for several weeks.

Because the CUBE only chills and carbonates a small reserve at a time, you get cold sparkling water on demand without storing litres of carbonated water under your sink.

How much energy does a Quooker use?

A Quooker reservoir on standby consumes around 10 W — about 3 kWh per month. Reheating after a dispense uses roughly the same energy as boiling the same volume in a kettle, but because the tank only reheats the small amount you actually used (not a kettle full of water you didn't need), most households use less electricity than they did with a kettle.

How long does a Quooker last?

Quooker reservoirs are rated for 15+ years of household use, with a 2-year warranty as standard from the manufacturer (extendable to 7 years on the reservoir by registering on Quooker's site within six months of installation). The tap itself has no electronics — just mechanical valves and the LED ring — and is built to outlast the reservoir.

Buying a Quooker

If this is your first Quooker, the Quooker buying guide walks through choosing the right tap shape, reservoir size and finish. For shipping, warranty and installation specifics see our FAQ. Browse the full range of Quooker taps or our starter packs (tap + reservoir bundled).