The chart below shows the cost of operation for gas fired furnaces with various efficiencies.
To find out how much you can save follow these simple steps:
- Select the age of your furnace from the left hand column.
- Then, estimate the output of your furnace. The output can be found on the furnace plate.
- Your furnace can be 10% to 50% larger than the actual heating load. Therefore, you should subtract this amount from the BTU listed on your furnace.
- Your savings is the difference between the number in the row associated with the age of your furnace and the number in the “present” row.
YEARLY GAS FURNACE OPERATING COST COMPARISON CHART
As an example, a furnace was installed in 1987, and the size shown is 70,000 BTU. The actual output is probably around 50,000 BTU. At 50,000 BTU your current cost is approximated $1,037.50 per year. If you upgrade to a new 95% efficient furnace your cost would be $837.70 per year. You will save approximately, $199.80 per year.
The operating costs are based on an average Chicago winter. Also the cost of natural gas changes monthly and these numbers are based on a cost of $0.80 per therm. The operating costs will vary based on the indoor temperature maintained in the residence and whether the thermostat is set back during the night.