Condensation on windows occurs when the glass is cold enough for water to condense from the air. Upgrading to triple glazing or raising room temperatures can help, but neither addresses the root cause: excess moisture. The bathroom and kitchen are the main sources; keeping doors closed and using extractor fans or opening windows for at least 15 minutes after showering or cooking can prevent moisture spreading.
Drying laundry outside reduces indoor moisture. If drying indoors, place clothes near an open window. A dehumidifier costs about 7p per hour to run and works best in confined spaces. Tumble dryers are faster but more expensive: heat pump models cost £51 per year on average, while older vented or condensing dryers cost £130-£141 annually, according to Which?.
Wipe condensation off windows each morning to lower overall humidity. Dispose of wet tissues or cloths outside, or flush them down the toilet. A window vacuum (from £30) can suck water into a container for disposal.
Open windows briefly even in winter, as cold air holds less moisture. Follow the German practice of Stosslüften: open all windows for five minutes morning and evening to create a through-draught. Trickle vents in window frames allow constant air exchange without full opening.
Passive moisture absorbers cost from £8. One type uses calcium chloride crystals that drip into a tank; another uses silica gel beads that can be recharged in a microwave. These suit small spaces like cupboards or caravans. Electric dehumidifiers (from £100) are the most effective solution, automatically maintaining humidity levels.
