2 system one time inspection. Found upstairs furnace to have suspected misplaced room sensor causing average temperature to be wildly off allowing furnace to run constantly. Removed sensor from thermostat and system performed properly. Inspected unit finding system to have duct board plenums, no wet switch and ac starting to get dirty. Main floor system is 80% furnace in an encapsulated crawl space causing incomplete combustion to rust heat exchanger out prematurely. Incomplete combustion could be smelled by both Dominique and myself in crawl space. Heat exchanger has large amount of rust, a small missing section of metal and a few cracks that were located. Informed customer of safety concerns with heat exchanger in the condition it is in and advised not to operate main floor heat. Left thermostat in non heating position. Found main floor furnace does not have secondary emergency drain pan in crawl space, condensate pump is dirty and ac getting dirty as well. Quoted repairs.