Yes, a portable heater for a car can be good—especially in cold climates or for older vehicles with weak built-in heating. It provides quick warmth and helps defrost windows. However, its effectiveness depends on the model and power source. 12V heaters that plug into your car’s cigarette lighter are common, but they may not be very powerful. For best results, choose a well-reviewed unit and use it as a supplement, not a full replacement.