A ‘magic’ button defrosts a car’s windshield in seconds – and some drivers had no idea

Turn on the air conditioning: even in winter, it helps reduce humidity.
Keep your windows clean: dirty windows keep fogging up.
Always stay nearby: leaving the engine running unattended can be risky, or even prohibited in some cases.
The alternative for older cars
If your car does not have a demisting button, you can opt for other effective solutions:

Use a commercially available defrosting spray.