Energy saving defog/device operation strategy and control scheme for vehicles

An energy-saving method for operating a climate control system for providing heated air to an interior surface of a windshield of a vehicle, said method comprising:

• a) receiving a plurality of inputs, wherein said plurality of inputs includes an ambient outside temperature, a climate control discharge temperature, and an operational status of a defogging control system;
• b) determining a first control criterion value, said first control criterion value being dependent only upon said ambient outside temperature;
• c) activating a heating element in response to said operational status and if said first control criterion value is less than said climate control discharge temperature;
• and
• d) activating an air-conditioning system and said heating element in response to said operational status and if said first control criterion value is greater than said climate control discharge temperature.

An energy-saving method for use with a climate control system for providing heated air to an interior surface of a windshield of a vehicle, said method comprising:

• a) receiving an ambient outside temperature from a first temperature sensor;
• b) receiving an interior air temperature from a second temperature sensor positioned at a point in an air passage, said point being positioned downstream from a heating element, and said heating element being positioned down stream of a cooling element;
• d) determining a criterion value, said criterion value being dependent upon only said ambient outside temperature;
• e) controlling said heating element to add heat to said heated air if said interior air temperature is greater than said criterion value;
• and
• g) controlling said cooling element to cool said heated air before said heating element adds heat to the heated air if said interior air temperature is less than or equal to said criterion value.