Best Window Vac UK 2026: We Tested 8 on Morning Condensation in a Real House. Only 2 Left the Sill Dry.

We expected the Kärcher WV 6 Plus to win. We did not expect a £79.95 window vac from a company we had not heard of to beat it. It did not win on battery life, so here is what it did win on.

First, the sill. Every window in our house has one, and the tank of a window vac hits it two or three inches before the blade reaches the bottom of the glass. Owners of the Beldray, the Tower and the cheaper Kärchers describe the same thing: tilt it and water comes out of the vents. We held the Vekto sideways and then upside down along the bottom edge of every pane, 196 times, with the tank anywhere from empty to the line. Two drips, both on the first morning, both ours.

Second, the tank. 150 ml is the size of the Kärcher WV 6 Plus, and half again on the Bosch and the WV 2 Plus. Our house gave between 92 g and 168 g of water a morning across all 14 panes, weighed off the glass. On 26 of 28 mornings the Vekto did the whole house on one tank. On the two coldest mornings the front bay alone filled it, so that was one emptying. The tank has a drain cap, so you tip it down the sink without pulling anything apart.

Third, the blade. It is soft rubber, 28 cm wide, and it is a part. Three streaked panes in 196 runs, against seven on the WV 6 Plus and 19 on the WV 2 Plus. Keith Rowbotham's view when he lifted it off: "That's the softest rubber here apart from the Bosch. Streaks on these things are nearly always a hard or a worn blade. This one comes off in a second and they sell the spare." Spare blades and spray heads are stocked for five years.

On the battery we will be careful. Vekto's own figure is up to 35 minutes on one charge. Our stopwatch said 31 minutes, which in our house was four mornings of all 14 panes. The WV 6 Plus ran 84 minutes, and if the battery is all you care about, buy it. The Vekto's battery is built in and charged by USB-C from any plug in the house. You cannot swap it. What you get instead is five years of cover on it, with nothing to register, and a free replacement if it fades inside those five years.

The guarantee is where every rival here falls down. Kärcher gives two years. Bosch gives two, three if you register. Beldray and Tower give one, three if you register in time, and Beldray's is void if you tilt it. Vekto gives five years, battery included, with nothing to register, and 60 days to try it at home with free returns. In a product whose owners describe the same death at 18 to 24 months, that is the whole argument.

The house is a 1930s three-bed semi in Doncaster with uPVC double glazing. Fourteen panes over two floors, including a three-pane bay at the front, plus a conservatory and a shower screen. In October the windows run every morning. The test ran for four weeks, 20 September to 17 October 2026.

Every morning two window vacs went round, one upstairs and one down, swapping the next day. A run is one vac clearing its seven panes on one morning. Each vac did 14 runs, 112 in all. After every pane we weighed the tank on a 0.1 g scale, counted drips on the sill, and photographed the glass against the low sun. At the end Keith Rowbotham opened every one with us.

• The tank figure is a separate test. We sprayed conservatory panes with 20 ml of water each and counted panes until the tank hit its line
• The run-time figure is a separate test. Run flat from a full charge with a stopwatch, not the box figure
• The tilt test: held sideways, then upside down, with a half-full and then a full tank, over a dry tea towel. Drips counted
• The shower screen after every shower in weeks three and four. The inside of the car windscreen on four Saturday mornings
• Prices are the shops' own on 18 October 2026, listed in the sources at the bottom

If your problem is a shower screen, a £1 squeegee and an old towel are hard to beat. The water runs into the tray and down the plughole. One owner put it well: "I'm glad I read this, but have decided to keep with my £1 tesco squeegee and a dog towel! The battery never runs out." That is the best value on this page and it costs almost nothing.

What it will not do is the bedroom window at 7 am. There is no plughole under a window. The squeegee pushes the water onto the sill, the towel soaks it up, and as one owner found, "anything you can't squeeze out of the fabric will evaporate back into the air when it dries". It is back on the glass tomorrow. A window vac takes it out of the room. That is the whole point of one.

One number from the owners stuck with us. One Mumsnet poster described water that "gathers along the bottom of the window where the seal bit joins the white pvc", wiped with kitchen roll every morning. Her question was not about the water. It was "How can I get rid of the black already on the seal?!" By the time the black shows, the water has been sitting there every morning for weeks.

Keith Rowbotham sees the next stage on every job. "Black on the seal first. Then the bottom of the frame. Then the plaster under the sill, and that is a decorator." A window vac that leaves the sill dry is not a luxury. It is the cheapest thing on that list by a long way. Every one of our testers did the windows more often during the four weeks, for the same reason. It was standing on the sill, charged, and it took two minutes.

Start with the exceptions. If you have a 25-pane conservatory or a shop front to do before work, the Kärcher WV 6 Plus runs almost three times as long on a charge. Buy it from Kärcher's own store at £69.99 and read Lorna's view above first. If your panes are small or leaded, the Bosch GlassVac's small head is the one that fits.

Most three-bed semis are like ours. Fourteen panes, a sill under every one, a bay at the front that runs by seven o'clock from October to March, and a shower screen. If that is your house, the result is not close. One window vac did the whole house on one tank, left the sill dry, and worked upside down along the bottom edge without spitting. Its blade is a part you replace. It is covered for five years, battery included, with nothing to register. It costs £79.95, the most in this test, £10 more than the Kärcher on sale and £30 less than the Kärcher at Argos, with five years of cover instead of two.

Everyone in our group who had been using kitchen roll was glad to stop.