A car expert has explained whether people should use hot or cold air when defogging their car windscreens – and it turns out there’s a rather nuanced approach
Drivers have been advised on how to defog their car windows (stock)(Image: Howard Kingsnorth via Getty Images)
A motoring expert has clarified whether warm or cool air should be utilised when drivers are defogging their vehicle windscreens. Wet weather is expected to strike the UK this weekend with the Met Office indicating that all regions of the country could experience rainfall.
Besides coping with driving in damp conditions, it also generates a familiar irritation for motorists – steamed-up windscreens. This occurs as warm, humid air inside vehicles transforms into liquid water droplets when it contacts the windscreen, which has become cold due to the external rain.
To address this, a typical solution is to employ your vehicle’s fan. But should you utilise warm air or cool air?
We consulted motoring expert Ian Edwards to discover – and it appears there’s a fairly subtle approach drivers should adopt.
Ian recommended: “Rather than immediately blasting the windscreen with the hottest air, start cooler and gradually increase the temperature as the glass clears.
“Using the air conditioning at the same time can speed things up by drying the air inside the car, while most modern cars also have a dedicated demist setting that does much of the work for you.”
Besides progressively shifting from cool air to warm air to defog a windscreen, Ian also recommended avoiding a particular setting inside the vehicle too.
He stated: “The quickest way to clear a fogged-up windscreen is to turn on the demister, direct the fans at the glass and switch on the air conditioning, which helps remove moisture from the air.
“Keep air recirculation off so you’re bringing in fresh air, and avoid wiping the glass with your hand as this can leave smears that make visibility worse.”
Ian, Young Driver Expert at Veygo by Admiral, is not the only specialist to have offered guidance, with the RAC having suggested last year that motorists could clean their windscreen with shaving foam to create a temporary barrier.
They explained: “A handy tip to go the extra mile is to actually clean your windscreen with shaving foam.This protective barrier won’t last forever and may need to be repeated regularly, but a windscreen cleaned with shaving foam will be less likely to mist up. It’s a little trick ice hockey players use to stop their face masks from steaming up when they’re on the ice.”
They noted that the method would need to be carried out on more than one occasion before it proved truly effective.
Both Ian and the RAC’s guidance could prove particularly useful should drivers encounter rainfall this week and over the weekend, with showers expected to begin today (September 17) and persist through to Friday.
Met Office meteorologist Emma Salter outlined just how widespread the conditions would be: “Those showers will continue through Thursday night across Scotland and parts of Northern Ireland.
“Elsewhere, these showers will gradually start to ease through Thursday night and into Friday morning. It will be a clear, bright, and sunny start across the South East, however, elsewhere, we will see the cloud start to thicken and lower through Friday.”
