Not all cars have air recirculation buttons, especially older vehicles which normally have fewer technological elements.
New vehicles are often equipped with sensors that monitor the cabin air and moisture levels, adjusting the air circulation automatically.
In recent weeks, drivers across the UK have seen a cold snap which has brought freezing temperatures, ice and snow across much of the country.
With many looking to clear their windscreen in the morning, some have taken to social media to share their own tips.
source: express.co.uk