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
SEER2 numbers are approximately 4.5% lower than equivalent SEER numbers:
| 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 Minimum for Texas (South Region)
Effective January 1, 2023 — Equipment below these thresholds cannot legally be installed in Texas.
| Equipment Type | Capacity | Minimum SEER2 | Old SEER Equiv. |
|---|---|---|---|
| Split-system AC | <45,000 BTU | 14.3 SEER2 | ~15 SEER |
| Split-system AC | ≥45,000 BTU | 13.8 SEER2 | ~14.5 SEER |
| Heat Pumps | All sizes | 14.3 SEER2 | ~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)
- 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) |
Tax Credit Qualification
AC ($600 credit)
- SEER2 ≥ 16
- EER2 ≥ 12
Heat Pump ($2,000 credit)
- SEER2 ≥ 16
- EER2 ≥ 12
- HSPF2 ≥ 9
Learn more about federal tax credits →
Stack tax credits with utility rebates from Oncor and CoServ to maximize your savings.
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)