Best Window Vacuums UK 2026: For Condensation and Streak-Free Glass

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Every cold morning, the same job. Windows streaming with condensation, a tea towel that ends up soaked, and a damp windowsill that eventually goes black in the corners. A window vac turns that into about thirty seconds per window, with nothing left to dry.

It is worth being clear about what you are buying, though. A window vac deals with the water on the glass, not the reason it is there. Condensation means the air in the room holds more moisture than the cold glass can take, and clearing it every morning is the alternative to fixing that. If the same windows stream every day, or you are seeing mould on the frames, read our guide to the best dehumidifiers for small UK homes alongside this one. Most people who buy both end up using the vac far less.

Quick picks

How the four compare

Two columns decide most of this. Runtime matters only if you have a lot of glass: thirty minutes clears the windows in a typical flat several times over, while a four-bedroom house with a conservatory is where a hundred minutes starts to earn its money. The second nozzle matters more often than people expect, because a 280 mm blade will not fit between glazing bars or into the corner of a shower screen.

What to look for

Runtime and charge time. Most of these run 30 to 45 minutes and take two or three hours to charge, so a vac that dies halfway means waiting until tomorrow. Buy more runtime than you think you need if you have a lot of windows.

Two nozzle widths. The wide blade does a pane in one pass. The narrow one is for glazing bars, small panes, car windows and shower screen corners. A vac with only the wide blade will leave you wiping those by hand.

Weight. These are held above your head for minutes at a time. There is a real difference between 730 g and 1.2 kg by the last window.

Leaks and longevity. The two complaints that recur across this whole category are water leaking from the tank and the battery or charger failing after a few months. Neither is universal, but both show up often enough that guarantee length and spare part availability are worth reading before you buy, and they are in the table above for that reason.

The narrow nozzle is the reason this is the pick rather than the WV 6 below. Most UK homes have at least some small panes, glazing bars or a shower screen with an awkward corner, and a 280 mm blade skates straight over them.

Ten years of spare part availability is unusual enough to mention. In a category where the common failure is a battery or a charger rather than the vac itself, being able to buy the part that failed is worth more than a slightly better price.

Runtime is the only real reason to choose this over the WV 2. On a normal set of windows, 35 minutes is already more than a morning’s work, so the extra battery only matters when the job is genuinely big or you resent charging things.

The missing narrow nozzle is the catch. It is sold separately, but by the time you have bought one you are close to the price of a second vac, so check what your windows actually look like before choosing this one.

The weight is the standout number. At 730 g it is around a third lighter than the WV 6, and window vacs are used with your arm up, often at full stretch above a kitchen sink. That difference is felt long before the battery runs down.

Owners comparing it directly with a Kärcher generally rate it as well on glass, which is the part that matters. Where it gives ground is the supporting detail: a smaller tank, more noise, and five years of spare parts rather than ten.

This is an honest trade rather than a bad buy. Owner reports of failures at around two months are frequent enough to expect trouble, and Tower covers it for three years if you register online. That works only if you keep the paperwork and are willing to make the claim.

Register it on the day it arrives, not when something goes wrong. The extra two years depend on registering, and the failures owners describe fall comfortably inside that window.

Worth buying alongside

A proper glass concentrate. Washing-up liquid is the usual choice and it is the usual reason for streaks, because it leaves a film. A dedicated concentrate dilutes to litres of cleaner and lasts a season or more. Kärcher’s RM 500 makes four litres from a 500 ml bottle.

See Kärcher RM 500 concentrate

Unger’s professional FR100 is the cheaper option per litre, diluting at 1:100.

See Unger FR100 concentrate

An extension pole, if you have a conservatory roof, a stairwell window or anything else you currently need a ladder for. Kärcher’s set includes both an extension lance for the vac and a pole with a microfibre head for washing.

See the Kärcher extension set

Which window vac should you buy?

For most homes, the Kärcher WV 2 Plus N. Both nozzle widths, enough runtime for a morning, and more owner feedback behind it than anything else here. If you have a lot of glass, a conservatory or patio doors, the WV 6 Plus and its hundred minutes make more sense.

On a budget, the CubeTECH CTWV2 gives you both nozzles and the lightest body here for far less. And the Tower is the one to choose if a three year guarantee matters more to you than the odds of needing it.

Check the Kärcher WV 2 Plus N on Amazon

Window vac buying guide: your questions answered

Will a window vac stop condensation coming back?

No. A window vac removes the water from the glass, but the moisture is still in the room and will condense again on the next cold morning. It is a quick, effective way to manage the symptom, and it stops water running onto sills and frames where mould grows. If the same windows stream every day, the cause is too much moisture in the air: drying washing indoors, cooking without the extractor on, or poor ventilation. A dehumidifier deals with that, and most people who own both use the vac far less afterwards.

Why is my window vac leaving streaks?

Usually the cleaning liquid rather than the vac. Washing-up liquid leaves a film that streaks as it dries, so use a proper glass concentrate diluted as instructed, and go easy on it. After that, check the rubber blade for nicks or grit, wipe it clean before you start, and work in overlapping passes from top to bottom rather than side to side. Cleaning in direct sunlight also causes streaks, because the glass dries before the blade reaches it.

How long does a window vac battery last?

Between about 30 and 100 minutes depending on the model, and charging takes two to three hours, so running out means waiting rather than carrying on. Thirty minutes covers the windows of a typical flat several times over. A large house with a conservatory is where a longer runtime genuinely earns its price. Battery and charger failures are the most common complaint across this category, so check the guarantee length and whether spare parts are sold before buying.

Can you use a window vac on shower screens and car windows?

Yes, and for many owners that is where it gets the most use. Shower screens, mirrors, tiles and car glass all work the same way as a window. The one thing to check is nozzle width: a 280 mm blade will not fit into the corner of a shower cubicle or between the glazing bars on a car window, so a model with a narrow second nozzle is far more useful for those jobs.

Do window vacs work on the outside of windows?

They do, though they are designed mainly for indoor use and for condensation. Outside, the limit is usually reach rather than the vac: anything above ground floor needs an extension pole, and working up a ladder with one is not worth the risk. For upstairs windows, an extension set or a professional window cleaner is the sensible answer.

What is the best liquid to use in a window vac?

A dedicated glass cleaner concentrate, diluted according to the bottle. They are designed to lift grease without leaving a film, and a 500 ml bottle of concentrate typically makes several litres. Avoid washing-up liquid, which streaks, and avoid using more than the recommended amount, since extra detergent makes streaking worse rather than better. Never put neat cleaner in the vac’s tank: it is a dirty water tank, not a dispenser.

Do I need to empty the tank every time?

Yes, and rinse it. Dirty water left standing in a sealed tank turns stale and can leave a smell that transfers to the glass next time. Emptying takes seconds, and on most models the tank comes away for rinsing under a tap. It is also worth wiping the blade after each use, since grit dried onto the rubber is what puts fine scratches on glass.