To use this chart: 1._Use the map above to locate the color zone where you live. 2._Determine the SEER/HSPF of your current system. __Typically, > 10 years old = 6.0 SEER/5.0 HSPF __5 - 10 years old = 8.0 SEER/5.6 HSPF __< 5 years old = 10.0 SEER/7.0 HSPF 3. Using the chart, cross reference your current SEER/HSPF with your color to determine your approximate annual cooling/heating cost. 4. Compare your annual cooling/heating cost to that of a new system with higher SEER/HSPF such as 10.0/7.0 or 12.0/7.8. 5. The difference of these two numbers is your estimated annual cost .