Heat performance tuneup times two systems. Change out filters client supplied. Inspect blowers, evaporators and ductwork. Tested all safety features high limits and roll outs. Tightened all wire connections. Cleaned flame sensor and inducer ports. Check heat exchanger for cracks, found none. No carbon dioxide or gas leaks detected in home. Checked thermostats for proper operations. Removed dead batteries that were starting to corrode out of both thermostats.Thermostats are powered by the furnace and do not need batteries. System operating at manufacture specs at this time.