1. A controller that integrates the control of heating or cooling in buildings by simultaneously controlling heating ventilation and cooling (HVAC) systems in concert with separate fresh air ventilation (FAV) systems by reacting to outside and inside conditions, wherein said controller comprises: a. an internal sensor that monitors temperature in a building, b. an outside sensor that monitors current outside air temperature, c. a microprocessor system that sets logical set-points based on mathematical algorithms that uses said internal and outside sensors, d. a user-programmable interface to said microprocessor system that enables a user to define time-based temperature set-points for improved comfort in the building, e. a first switch relay controlled by said microprocessor system and said internal sensor and providing output based on the temperature of the building monitored by said internal sensor, and f. a second switch relay in series with the first switch relay, controlled by said microprocessor system and said outside sensor, and receiving the output from the first switch relay, wherein the second switch relay determines whether calls for cooling or heating are diverted to said separate FAV or HVAC systems based on the output from the first switch relay and the current outside air temperature monitored by the said outside sensor.