Performed single system heating maintenance. The system is a 2020 Gas furnace and it is zoned. I checked the electrical, cleanliness, drains, air quality, flame sensor, gas valve, and other safeties. The system is heating to manufacture specifications but I do have some concerns. Recommendations 1. The air advise machine indicated that the air quality is poor within the home and the customer stated that they have been sick on and off. I advise that an air scrubber be installed into the system to help regulate air contaminates and improve the air quality. The air scrubber uses ionizing technology to treat the air and make it easier to extract the contaminants with the filter by causing it to clump. 2. I recommend that the filter be upgraded to the Aprilaire line of filters. This allows the filter to last longer and provide superior filtration compared to the typical filter. 3. I noticed the system only has one float switch in the primary drain line. There is always a possibility