As winter tightens its grip, many across the UK are facing a familiar and frustrating battle: persistent condensation on their windows. For one London resident, the problem became so severe it felt like living with a "personal water feature". However, a simple, temporary solution using a common kitchen item provided surprising overnight relief.
The Relentless Damp of a London Winter
Ellen Jenne, who moved into her flat during a summer heatwave, found her first winter there to be a relentless struggle against condensation and mould. As temperatures plummeted, her windows began to "weep" every morning, forming significant puddles on the windowsills. Despite following conventional advice—opening windows, avoiding drying clothes on radiators, and using moisture absorbers like salt and cat litter—the core issue persisted. The salt worked only sporadically, and neither method offered a lasting solution.
The Simple Kitchen Cupboard Hack
Faced with the ongoing damp and the prospect of costly fixes, Ellen turned to a short-term suggestion: washing up liquid. The theory is that the detergent reduces the surface tension of water, causing moisture to spread evenly across the glass instead of forming droplets. This can prevent the large pools of condensation that lead to mould on frames and sills.
On the evening of 17 January 2026, she applied the method. After buffing the liquid directly onto the cold glass with a cloth—which also removed a surprising amount of grime—she waited to see if the hack would work. An important note from her experiment: using too much liquid can leave a soapy film and cause streaks, so a moderate amount is key.
Did The Washing Up Liquid Trick Work?
The results were visibly positive the next morning. While small patches of moisture formed later in the day, the windows remained largely clear of the heavy condensation that had been plaguing them. Crucially, the problematic puddles on the sill did not return to their previous levels. "It yielded overnight results, which was a delightful sight first thing in the morning," Ellen reported.
However, experts from GLRE Glazing Refurbishment caution that this is strictly a temporary measure. They advise that it "may not completely stop condensation, especially on colder days" and recommend applying it primarily to the bottom of windows where moisture gathers most. The underlying issues of poor insulation or ventilation require a permanent solution.
A Stop-Gap, Not A Solution
For renters or homeowners seeking immediate respite without investing in a dehumidifier, this washing up liquid method offers a quick and accessible fix. It highlights a widespread winter issue affecting many UK homes, where balancing heating costs with damp prevention is a constant challenge. As Ellen concluded, while a dash of detergent helps for now, tackling condensation and mould at their root is essential for long-term comfort and health.
