Arrived to do a dual system performance maintenance. Set systems for cooling. Measured each systems static pressure measured a temperature split between return and supply air. Checked interior of each furnace for cleanliness. Found that the fans for heating and cooling in each system are coated in dust. Went outside and verified refrigerant levels. Verified operation of all electronic and mechanical components. Found that a capacitor in the Lennox condenser is failing. Rinsed coils free of debris. Spoke with homeowner about the system. Air conditioning systems are operational at this time.