SIZING HEATING SYSTEMS Simple worksheets and formulas can help you size a heating system and evaluate energy improvements by Rick Karg Table 1 Design Weather Data for Selected Cities Outside Design Heating Temperature (97.5%) Degree Days Anchorage, Alaska -18 10860 Phoenix, Ariz. 34 1680 Little Rock, Ark. 20 3170 San Francisco, Calif. 38 3040 Denver, Colo. 1 6165 Hartford, Conn. 7 6170 Washington, D.C. 17 4240 Miami, Fla. 48 200 Atlanta, Ga. 22 2990 Boise, Idaho 10 5830 Chicago, Ill. 2 6640 Indianapolis, Ind. 2 5630 Cedar Rapids, Iowa -5 6600 Lexington, Ky. 8 4760 Portland, Maine -1 7570 Boston, Mass. 9 5630 Grand Rapids, Mich. 5 6890 Minneapolis, Minn. -12 8250 St. Louis, Mo. 6 4900 Cut Bank, Mont. -20 9033 Lincoln, Neb. -2 6050 Reno, Nev. 10 6150 Manchester,