My Escondido home from 1985 has its original AC, is it worth replacing now?
Almost certainly yes, for three reasons. First, a 1985-era AC unit is on its second or third equipment cycle at minimum, with original R-22 refrigerant systems particularly uneconomical to service today (refrigerant alone runs $150 to $250 per pound). Second, in Escondido's 9 to 10 month cooling season, a 1980s 8-10 SEER system uses roughly twice the energy of a modern 18-20 SEER heat pump for the same cooling output, typically $1,500 to $2,500 in annual energy waste. Third, current SDG&E rebates ($1,000 to $3,000) plus federal 25C tax credit (up to $2,000) cover 25 to 40 percent of replacement cost right now. Payback math on proactive replacement is usually 5 to 8 years on energy alone.