How your system works5 min readAugust 26, 2026
SEER2, HSPF2 and AFUE: what the efficiency numbers on a quote actually mean in DFW
SEER2 measures cooling efficiency over a season under a test that better matches real ductwork; the minimum for new split systems in Texas is 14.3 SEER2. HSPF2 is the same idea for heat pump heating, and AFUE is the share of gas a furnace turns into heat. In DFW, where cooling runs most of the year, each step up in SEER2 saves a meaningful amount, but above the mid-teens the extra cost takes longer to earn back than most people keep a system.
The three numbers
- SEER2: cooling output over a season divided by the electricity it used. Higher is more efficient. It replaced SEER in 2023 with a test that assumes realistic duct resistance, so a 14 SEER2 roughly equals an old 15 SEER
- HSPF2: the heating version for heat pumps. The federal minimum is 7.5
- AFUE: for gas furnaces, the percentage of fuel that becomes heat in the house. 80 percent is standard; 90 to 97 percent is condensing, with the white PVC vent pipe
The Texas minimums
Texas is in the federal Southeast region, where new split air conditioners under 45,000 BTU must be at least 14.3 SEER2 and larger ones 13.8. Heat pumps must be at least 14.3 SEER2 and 7.5 HSPF2 nationwide. A quote that lists a 13 SEER2 system for a home is quoting equipment that cannot legally be installed here; it happens with leftover inventory, so look for the number.
What a step up saves here
Cooling is the biggest line on a North Texas electric bill, so efficiency matters more here than in most of the country. As a rough rule, moving from 14.3 to 16 SEER2 cuts cooling energy by about ten percent, and from 14.3 to 18 by about twenty. On a home spending $1,500 a year on cooling, that is $150 to $300 a year. Variable-speed systems at the top of the range also run quieter and hold humidity better, which is a comfort gain that does not show up in the math.
Where it stops making sense is the top tier on a budget. A system that costs $5,000 more to save $300 a year takes 17 years to pay back, longer than most people own the house. The efficient middle, with a two-stage or variable-speed blower and sealed ducts, is where most of our area's homes land.
The number that matters more
A 20 SEER2 system on ducts that leak 25 percent performs like a 15. Efficiency ratings are measured in a lab with perfect airflow. Before paying for a higher rating, pay for a duct test and a load calculation; the installer who skips those is selling a number, not a result.
Questions on this
Do higher SEER2 systems qualify for rebates?
Sometimes, through the electric utility or federal tax credits, and the thresholds change yearly. Ask the installer to put any rebate on the quote in writing with the program name rather than promising it verbally.
Is a 97 percent furnace worth it in Texas?
Heating hours here are short, so the gas savings from 80 to 96 percent are small. The condensing furnace is often chosen for other reasons, like venting through PVC when the old flue is a problem.