When we lived in Iowa, we had a gas furnace. In the winter we would set it at a temperature and it would come on and give heat and then would shut off and all was well. Now in South Dakota we have an electric furnace. We set the thermostat to 70. The furnace comes on and heats the house as normal but the fan keeps on running and running and sends out wo much cold air that it then cools the house back down to ver cold and then the cycle starts all over again. Any thoughts?