1. Age: read it off the label, don’t guess
The outdoor unit has a data plate with the model and serial number, and the manufacture date is printed there or coded into the serial. Ask your technician to read it for you. ENERGY STAR lists equipment “more than 10 years old” as a reason to consider replacing. That’s a reason to look at the numbers, not a deadline.
2. Refrigerant: what the system runs on
The same data plate names the refrigerant. R-22 hasn’t been made or imported in the U.S. since 2020, so every recharge comes from a shrinking supply. R-410A is different: the EPA says you can keep using and repairing an existing system. New central systems are built for R-454B or R-32. A new outdoor unit for those refrigerants has to be paired with an indoor coil approved for it, so ask your technician whether your coil can stay.
3. Efficiency: what the new minimum buys you
Since 2023, a new split-system AC under 45,000 Btu/h installed in Texas and the rest of the Southeast must be at least 14.3 SEER2. The longer your AC runs each year, the more an efficiency gap matters, and Bush Intercontinental averages about 111 days a year at 90°F or hotter (NOAA, 1991–2020 normals). Ask for the SEER2 of the matched system, not just the outdoor unit.
4. Repair history: look at the pattern
Keep your invoices. One failed part on a sound system is a repair. Refrigerant added every summer means a leak that was never fixed. The same system needing something every few months means more parts are wearing out together. Your paperwork shows the pattern better than memory does.
5. Comfort: is the house ever right?
If some rooms never cool or the house feels damp at the setpoint, a new box of the same size may not fix it. ENERGY STAR says humidity problems, dust and rooms that never get comfortable can come from leaky or poorly insulated ductwork, and that a system too large for the house won’t keep it comfortable because of frequent on-off cycling. Sizing is a calculation; our AC installation page covers it.
6. Ducts: the part nobody replaces by accident
ENERGY STAR says about 20 percent of the air moving through ducts in a typical house is lost to leaks, holes and poor connections. In many Houston homes those ducts run through a hot attic. A new system on tired ducts can disappoint; good ducts can stay. See duct repair.
Sources: ENERGY STAR, Guide to Energy-Efficient Heating and Cooling (PDF) · U.S. EPA, HFC phasedown questions · U.S. EPA, R-22 phaseout · U.S. EPA, refrigerant rules by sector · 10 CFR 430.32, DOE efficiency standards · NOAA, Local Climatological Data, Houston Bush Intercontinental. Checked November 2026.
