Use this map and chart to calculate your savings. First, use the map to locate the zone where you live. Then, find the AFUE rating of your current system. Then, use the chart to find your approximate annual heating costs. The difference between your current cost and that of a higher-AFUE unit is your estimated annual savings.

Potential Annual Heating Savings
Zone	65% AFUE	80% AFUE	92% AFUE	95% AFUE
1	$1,596	$1,297	$1,127	$1,091
2	$1,418	$1,152	$1,002	$969
3	$1,082	$875	$764	$740
4	$957	$777	$676	$654
5	$534	$474	$412	$399
(Based on the standard DOE test procedure. Furnace model: heating capacity of 70,000 Btu/hr. Usage assumption: 2,080 heating load hours per year. Assumed gas price: $0.40/therm, the Federal average gas price in the U.S.) * AFUE: The federal government has established Annual Fuel Utilization Efficiency (AFUE) ratings to allow you to compare the efficiency of furnaces. The higher the AFUE percentage is (e.g. 90%), the more efficient the furnace.