Hot water dispensers: How we test hot water dispensers

We monitored how long each hot water dispenser took to boil, just as we do for kettles

Temperature of water

Hot water dispensers boil water and then fill your waiting cup, so we check the temperature of the water once it reaches the cup to see if your tea will be too cold to drink, of if it’ll be perfect.

The temperatures we measured range from 88.1oC up to 93.2. To find out which hot water dispenser gives the hottest brew, head to our hot water dispenser reviews.

Speed

Many hot water dispenser make claims that they can product a mugful of hot water in less than a minute – so we’ve checked them all

We time how long it takes for the water to boil, then time how long it takes to fill up a mug, and we also check to see how long it takes for the hot water dispenser to stop dripping.

Volume of water dispense

Testing both the minimum and maximum settings, we’ve measured exactly how much water is dispensed, and how consistent it is.

The best hot water dispensers fill the cup up with exactly the same amount of water each time, whereas some models can vary between 50mLs or more with each run – which means if you use the same cup, it could be under- or over-filled each time.

The Tefal QuickCup: hot water at the touch of a button

Mug suitability

Using a range of mugs from 150ml up to 300ml (see features explained), we check to see how suitable each appliance is for different sized mugs.

If you have a favourite mug, we’d suggest measuring the capacity so you can choose the best hot water dispenser for you, or if there will be more than one person using the hot water dispenser it’s better to get a hot water dispenser with a variable dispensing setting, so you can change the volume of water given out.

Insufficient water in the tank

Nobody wants to end up with a half-full cup of tea, so we check what happens if you try to use the hot water dispensers when there’s not enough water in the tank.

We tested to see if they still boiled, and if they’d dispense anything less than the set amount.

Cancel/Stop button

If you change you mind mid-brew, then the cancel or stop should work immediately to stop the water, and stop your cup from overflowing.

Our lab experts timed how long it took to press the button and for the water to stop.

The best hot water dispensers stopped immediately, while the worst took up to 8 seconds to stop – this many not sound much, but when it only takes 10 seconds to fill a mug this isn’t very responsive.

Our lab experts assess how easy the controls are to use

How easy are hot water dispensers to use?

We check everything from the instructions, to the water tank, pressing the buttons, cleaning the outsides, and emptying the drip tray.

All the hot water dispensers we tested had non-removable water tanks; this means they can be filled much like you would a kettle – at the tap. It also means that emptying the water tank can prove difficult, and some can’t be fully emptied.

We’ve assessed how tricky the water tank is to use over all; taking into account the size and weight of the appliance, how big the filler hole is, and also if any covers, handles or any other parts of the hot water dispenser gets in the way while it’s trying to be filled.

Filling the jug at the sink is the worse case scenario, which is why we test using this situation, but we for a better experience, we recommend filling the appliance with a jug, rather than struggle with it under the tap.

Total test score

The Which? total test score for hot water dispensers ignores price and is based on: 

Overall ease of use and using the dispenser - 40%
Volume - 25%
Timings - 25%
Temperature - 5%
Build quality - 5%