The payback period is how long it takes your energy savings to offset the upgrade cost see typical
central air conditioner cost ranges to budget your upgrade. For example, if upgrading from a 10 SEER to 20 SEER2 AC saves $250/year and the upgrade (after rebates) costs $3,500, the payback period is 14 years. Since modern ACs last 15–20 years, that’s still financially positive that’s still financially positive, provided you keep up with basic
AC maintenance to protect that lifespan and electricity prices are likely to rise over that period, improving your actual payback.