SEER stands for Seasonal Energy Efficiency Ratio. It measures how much cooling a system delivers over a typical cooling season compared with the electricity it uses. Since 2023, new central air conditioners and heat pumps sold in the United States are rated using SEER2, an updated test procedure that better reflects real-world conditions such as static pressure from ductwork. A SEER2 number is not directly interchangeable with an older SEER label on legacy equipment, so compare bids using the ratings shown on the current EnergyGuide label.
Higher efficiency generally means lower operating cost, but it also usually means a higher equipment price. Whether the upgrade pays off depends on your climate, electric rates, how many hours you run cooling each year, and how long you plan to stay in the home. In hot, humid regions, efficiency gains can add up faster than in mild climates where the system runs fewer hours.
Minimum federal efficiency standards vary by region. A contractor may quote a 14.3 or 15.2 SEER2 unit as a baseline and offer 16, 18, or higher as upgrades. Ask for the exact model number and efficiency tier on each line item so you are not comparing unlike equipment. Rebates and utility incentives, when available, may require specific efficiency levels—verify eligibility before you count those savings in your budget.
Efficiency is only one part of value. Proper sizing, quality installation, and duct condition affect comfort and cost as much as the rating on the nameplate. A moderately efficient system that is correctly sized and installed often outperforms a premium unit that is oversized or poorly matched to the duct system.