What SEER Actually Measures
Over a typical cooling season
Simple Analogy
SEER is like MPG for your car. A 30 MPG car uses less gas than a 20 MPG car to travel the same distance. A 16 SEER AC uses less electricity than a 10 SEER AC to produce the same cooling.
SEER vs. SEER2: What Changed
January 1, 2023 Transition
DOE replaced SEER with SEER2 as the official efficiency metric. SEER2 tests use higher external static pressure (0.5" vs. 0.1"), representing more realistic installed conditions with actual ductwork.
SEER to SEER2 Conversion
For ducted split systems — what's in most North Texas homes — SEER2 lands about 5% below the old SEER number. This does not transfer to other equipment: ductless mini-splits convert about 1:1, and HSPF2 heating ratings fell roughly 15%. Don't apply a cooling derate to a heating number.
| Old SEER Rating | SEER2 Equivalent |
|---|---|
| 14 SEER | 13.4 SEER2 |
| 15 SEER | 14.3 SEER2 |
| 16 SEER | 15.2 SEER2 |
| 18 SEER | 17.1 SEER2 |
| 20 SEER | 19.0 SEER2 |
Texas Requirements
Federal Minimums Applying in Texas (DOE Southeast Region)
Effective January 1, 2023. The air conditioner numbers are regional — enforced on the installer, based on where the equipment goes in. The heat pump numbers are national — enforced on the manufacturer, based on when the unit was built. There is no Texas-specific heat pump rule; 14.3 SEER2 / 7.5 HSPF2 is the floor in all fifty states.
| Equipment Type | Capacity | Minimum SEER2 | Old SEER Equiv. |
|---|---|---|---|
| Split-system AC (regional) | <45,000 BTU | 14.3 SEER2 | ~15 SEER |
| Split-system AC (regional) | ≥45,000 BTU | 13.8 SEER2 | ~14.5 SEER |
| Packaged AC (national) | All sizes | 13.4 SEER2 | ~14 SEER |
| Split heat pump (national) | All sizes | 14.3 SEER2 + 7.5 HSPF2 | ~15 SEER |
Note: Existing systems aren't affected. Your 10-year-old 13 SEER system is legal to operate and repair — just not to replace with the same efficiency.
The Efficiency-to-Savings Math
Example: Upgrading from 10 SEER to 16 SEER
2,000 sq ft Texas home, 3.5-ton AC, 2,200 cooling hours/year, $0.12/kWh
Current (10 SEER)
$1,109/year
New (16 SEER)
$693/year
Annual Savings: $416
Savings by Upgrade Path
| From | To | Annual Savings* | 10-Year Savings |
|---|---|---|---|
| 10 SEER | 14.3 SEER2 | $280-$350 | $2,800-$3,500 |
| 10 SEER | 16 SEER2 | $350-$420 | $3,500-$4,200 |
| 10 SEER | 18 SEER2 | $400-$480 | $4,000-$4,800 |
| 10 SEER | 20 SEER2 | $450-$540 | $4,500-$5,400 |
| 14 SEER | 16 SEER2 | $80-$120 | $800-$1,200 |
| 14 SEER | 18 SEER2 | $140-$180 | $1,400-$1,800 |
*Estimates for typical 2,000 sq ft Texas home, $0.12/kWh
Is Higher SEER Worth It?
Equipment Cost Premium
Simple Payback
Key Insight
Going from minimum (14.3) to moderate efficiency (16) often makes sense. Going to very high efficiency (20+) rarely pays back within equipment lifetime unless you have very high usage or electricity rates.
When Higher SEER Makes Sense
- Very high usage (larger homes, extreme patterns)
- Higher electricity rates ($0.15+/kWh) — check your rate
- Plan to stay 10+ years
- Comfort priority (variable-speed = better humidity)
When Higher SEER Doesn't Make Sense
- Near end of homeownership
- Budget constrained (proper sizing matters more)
- Low usage (smaller home, not home during day)
- Rental property (won't capture savings)
Recommended SEER Targets for Texas
| Priority | Target SEER2 |
|---|---|
| Budget-conscious | 14.3-15 SEER2 |
| Balanced | 16-17 SEER2 |
| Efficiency-focused | 18-20 SEER2 |
| Premium comfort | 20+ (variable-speed) |
Which Efficiency Tiers Actually Matter
The federal 25C tax credit expired for equipment placed in service after December 31, 2025. Two efficiency bars still matter when you're shopping — the legal floor you can't go below, and the ENERGY STAR line that utility rebates key off.
Legal minimum (Texas)
- Split AC <45,000 BTU: SEER2 ≥ 14.3
- Split AC ≥45,000 BTU: SEER2 ≥ 13.8
- Packaged AC: SEER2 ≥ 13.4
- Split heat pump: SEER2 ≥ 14.3, HSPF2 ≥ 7.5
ENERGY STAR split heat pump
- SEER2 ≥ 15.2
- EER2 ≥ 11.0
- HSPF2 ≥ 7.8
A heat pump has to clear all three of those numbers, not just the SEER2 one. The 8.5 HSPF2 figure quoted on a lot of sites is the Cold Climate criterion for non-ducted equipment — a different program with different rules. Central AC has its own ENERGY STAR criteria; ask your contractor for the current threshold and the AHRI certificate rather than trusting a number off a blog.
Check current utility rebates from Oncor and CoServ before you sign anything.
The Installation Factor
A poorly installed 18 SEER system may perform worse than a well-installed 14 SEER system.
Common installation problems that eliminate efficiency gains:
- • Improper refrigerant charge (±5-20% efficiency loss)
- • Duct leaks (15-30% efficiency loss)
- • Undersized ductwork (restricts airflow)
- • Improper airflow (reduces capacity and efficiency)