01/27/2026- I arrived on site to find the furnace heating properly but at a lower efficiency due to an extremely dirty air filter. After I replaced the air filter with the customer provided filter I was able to confirm that the unit is heating properly with an over 30 degree temperature split between the supply and return side of the unit. The other potential factor as to why this unit is running often is due to how poorly insulated this house is, causing the warm air to escape outside often. However I have verified that the unit is heating properly at the time of service.