Well I bought one for a little Peugeot Ion which suffered hugely from condensation in the autumn as we didn't use the heating (due to range) and it made an instant difference. Got others for a Renault Twingo and the kids' old Citroen C1 (with semi-leaky boot). If placed on the dashboard and properly dried, then they certainly cleared the problem up. Obviously less humid now. And obviously if you have a leaky car, sorting that out first is important but even new cars can suffer from condensation in the sun. So I would recommend!