What Is Pure Water Window Cleaning?
If you've seen a window cleaner working with a long pole and no bucket, no squeegee, and no chamois leather, they were probably using a pure water system. It looks different from traditional window cleaning, and a lot of customers ask us how it actually works.
The basic idea
Tap water contains dissolved minerals. Calcium, magnesium, and other trace elements are present in varying amounts depending on where you live. Northamptonshire has hard water, which means relatively high mineral content. When tap water dries on a surface, those minerals get left behind as white spots and streaks.
Pure water systems remove those minerals before the water touches your windows. The water passes through a series of filters, including reverse osmosis membranes and deionisation resin, until all the mineral content has been stripped out. What's left is water with a total dissolved solids (TDS) reading close to zero.
When that purified water dries on glass, nothing gets left behind. The finish is clear.
What we add: heat
Most pure water systems use cold water. Ours is different. Our Thermo Pure system heats the water to around 80 degrees Celsius before it goes through the poles. Hot water dissolves and lifts dirt more effectively than cold water. You can test this yourself: try washing a greasy plate in cold water versus hot. Same principle applies to window grime, bird droppings, tree sap, and the general film of pollution that builds up on glass.
The combination of heat and purity is what gives us a better result than most competitors. The hot water does more of the cleaning work, and the deionised water dries without leaving marks.
How the poles work
The water is pumped through interlinking carbon fibre or fibreglass poles that extend up to 65 feet from ground level. A brush head at the end of the pole agitates the dirt while the heated water flushes it away. The cleaner works from the ground, controlling the brush angle and water flow to cover the entire pane.
This means no ladders leaning against your property. No one standing on your windowsills or conservatory roof. The risk of damage to your property drops to nearly zero, and the risk to the person doing the work drops with it.
Why the glass stays wet
This is the question we get asked most. After a traditional squeegee clean, the window is dry immediately. With a pure water system, the glass is left wet and dries naturally over the next few minutes.
That thin film of water you see is deionised. It contains nothing that will leave a mark when it evaporates. If you wipe it with a cloth before it dries, you might actually make it worse, because the cloth introduces fibres and oils from your hand. Leave it alone and it dries perfectly clear.
Is it better than traditional cleaning?
For exterior windows, yes. The pure water system cleans the glass, the frame, and the seal in one pass. Traditional methods focus on the glass and ignore the frame, which means dirt from the frame runs back onto the glass the next time it rains.
For interior windows, traditional methods still work well because you can wipe and polish the glass by hand. We use traditional methods inside and pure water outside when customers want both done.
Does it work in the rain?
Yes. Rainwater is relatively clean. The marks you see on windows after rain come from dust that was already sitting on the glass mixing with the water. If the glass is clean, rain just runs off. Our FAQ page covers this in more detail.
If you want to see the difference on your own windows, get a quote. We cover Northampton, Kettering, Wellingborough, and everywhere in between.