I have a small 2-seater car (2002 Honda Insight), and bought 2 de-humidifiers, which should be overkill for such a small car. If you bought these to keep your windshield/windows from getting foggy like during a cold rain or snow, don't bother. I even bought a box of cat liter in a large pan in the hatchback for more surface area to help combat dampness and fog, and that didn't do anything either. Nice idea to keep moisture down, but not a magic fix for window fogging. Marc Matczak Waterford, Pa.