Upon arrival, inspected system and found unit was struggling to exhaust heat from furnace heat exchanger. Unit had multiple high limit trips. Causing it to go into soft lockout. Upon discussing with Harry his 1 inch filters were only two weeks old, but there is an excessive amount of dust in the air quickly blocking filter filters. Informed Harry of potential humidifier, causing excessive dust. Recommend running filtered water in humidifiers. And changing filters once a month until problem subsides but 16x25x1 filters are good for 1-3 months max typically. On these systems he may get 2 months max being high demand.