Gas furnace straight ac unit inspection to check lifespan and efficiency of unit. Turned unit on upon arrival and found system condenser fan motor bearing loud - amperage of motor towards high end of manufacturer specifications but still in range and operable - bearing may fail in the near future. Found system low on r22 refrigerant causing system not to cool efficiently - estimate system missing about half of its 6.5 lbs charge meaning would need about 3 lbs of refrigerant to bring in line with manufacturer specifications. This is indicative of a refrigerant leak. R-22 refrigerant was phased out by the EPA in 2016. Furnace heat exchanger beginning to rust out. Furnace burners rusted and beginning to degrade. Whole system installed in 2005 and approaching the end of its serviceable life. Recommend replacement of furnace and ac system.