Heater Hotter(TM) solves the problem of slow warm up times and waiting for your vehicle to thaw in winter months.Heater Hotter is specially formulated to accelerate the transfer of heat from the engine to the antifreeze in frigid climates. It allows your HVAC system in your vehicle to operate more efficiently, and for you to get comfortable, ice melting, window defrosting warm air up to 50% faster in even sub-zero temperatures. Heater Hotter is safe to mix with all types of anti-freeze.