Engine and cabin heating problems associated with cold starts at subzero conditions are greatly reduced by use of a Heat Battery. This is a latent heat store, collecting waste heat from the engine and storing it by use of efficient heat insulation. On the next cold start the heat is released with high initial power. The performance increases with colder environment conditions. Startability of the engine and the warm-up performance are improved. Emissions of hydrocarbons and carbonmonoxide are reduced up to 80 % in the CVS test at -7°C (20°F) and Diesel noise is lowered.The windshield is cleared of ice and frost and kept free of mist. Passenger comfort improves since hot air flows into the cabin within seconds after the Heat Battery is engaged.