Our Bryant gas furnace (no sure how old, but it's no spring chicken) stopped blowing heat, all rooms get cold air instead. The switch was on 'heat' and the temp was set around 70. After I switched the thermostat from 'heat' to 'off', air continued to blow and wouldnt stop, so I turned off power to the furnace for now. Its freezing out and emergency service calls we made are going to cost $200 just to get someone to our door. (Its Saturday), so Im hoping we can find a solution ourselves, or at least tide us over til Monday.

One serviceman suggested over the phone that if we hadnt changed our filter in a while (which we are guilty of), that it could cause this and a technician needs to reset the furnace.

Any ideas? Thanks!