*only applies if rated cooling output and operating schedules remain the same after upgrade, otherwise energy consumption in kWh must be calculated separately for existing and projected running conditions
R-410a: new standard, more efficient, no ozone damage, higher pressures (requires tougher, more durable parts, increasing life of system)
R-22 (freon): old standard, illegal in any system manufactured after 2010, no longer imported or manufactured after 2020. Less energy efficient (heat transfer), contributes to depletion of ozone, rising prices.
Efficiency: ratio of cooling output (BTU) to heating input (watt-hours) (unit = BTU/Wh)
Energy Efficiency Ratio (EER): fixed set of operating conditions (Tindoor = 80F, Toutdoor = 95F, relative humidity = 50%)
Seasonal Energy Efficiency Ratio (SEER): averages performance across a range of outdoor temperatures typical of the cooling season.
Estimated Capacity: BTU/Hr
US DOE: 3% degradation for unmaintained, 1% for completely maintained systems