Alan in Ottawa, Ontario is complaining about the air conditioning going all the time because the thermostat seems to be reacting to the kitchen heat, and the upper and lower floors of his house do not have an even temperature at all.
Two problems here. First the thermostat should not be near any heat or cold source. Hence it should not be in the kitchen, nor in a draftee hallway, or anywhere where the sun can strike it. Neither should it be installed on an outside wall. We will usually tuck it away on a convent wall in the living room, where we actually want the most controlled atmosphere of the whole house. The only solution to that one is to move the thermostat.
As for the imbalance of heat or air-conditioning between he first and second floors, you need to play with the balancing dampers above the furnace. Damp down the flow of air to that part of the house that gets too much (hot or cold) and open the dampers to that part of the house that is comfortable. That will force the furnace, or air conditioner, to work a bit harder but the results will be more even.