What maintenance task can improve the efficiency of a gas furnace?

Regular cleaning of the burners is a key maintenance task that significantly improves the efficiency of a gas furnace. Over time, dust, debris, and soot can accumulate on the burners, which leads to incomplete combustion of the fuel. When combustion is incomplete, it not only reduces the furnace's overall efficiency but can also increase harmful emissions.

By keeping the burners clean, the furnace can achieve a more efficient combustion process, resulting in better heat production from the same amount of gas. This means that less fuel is required to achieve the desired temperature, which not only saves money on energy bills but also reduces the environmental impact.

In contrast, while other options may seem beneficial, they do not have the same direct impact on the efficiency of the combustion process. For instance, replacing the thermostat annually may help ensure accurate temperature readings and comfort but does not directly enhance furnace performance. Installing a new gas line is relevant for safety and proper gas flow but does not improve efficiency unless the existing line is severely inadequate. Upgrading furnace insulation can have benefits related to heat retention and overall energy usage in a home but is not a direct maintenance task for the furnace itself.