Performed Precision Heating Tune Up on Lennox Gas Furnace. The 16x25x4 Air Filter is very dirty and needs to be changed. Homeowner is going to purchase and replace Air Filter. Recommend replacement of the Air Filter every 6 months rather than every year due to the condition of the current filter. Cleaned and serviced humidifier. Tested humidifier and set to 35% Humidity at the Thermostat. Inspected electrical components and cleaned furnace tubing and drain lines. Cleaned condensation pump and tested. Performed Combustion Analysis on Furnace. The Air Scrubber for the system is receiving 24Volts but the indicator light is not lit. Would recommend replacement of the Cell and then retesting unit. Water heater is 12 Years old. Would recommend replacement of the Water Heater before any issues or failure occurs. Average life of residential water heaters is 10-12 Years. Included estimate for replacement of the Air Scrubber Cell and one for the Water Heater Installation.