SEER Rating Guide: What It Means & Why It Matters
SEER Rating Comparison Table
| SEER | SEER2 (2023+) | Efficiency Class | 3-Ton Annual Cost* | Savings vs SEER 14 |
|---|---|---|---|---|
| 14 | 13.4 | Minimum (legacy) | $1,100 | — |
| 15 | 14.3 | DOE Minimum (2023) | $1,027 | $73/yr |
| 16 | 15.3 | Standard | $963 | $137/yr |
| 18 | 17.2 | High Efficiency | $856 | $244/yr |
| 20 | 19.1 | Premium | $770 | $330/yr |
| 25 | 23.9 | Ultra Premium | $616 | $484/yr |
*Based on 3-ton unit, 1,500 cooling hours/year, $0.15/kWh.
SEER vs EER vs HSPF
- SEER (Seasonal Energy Efficiency Ratio): Seasonal cooling efficiency. Total cooling ÷ total electricity over a cooling season.
- EER (Energy Efficiency Ratio): Instant efficiency at a specific condition (95°F outdoor, 80°F indoor). Better for comparing in hot climates.
- HSPF (Heating Seasonal Performance Factor): Heating efficiency for heat pumps. Higher = better.
The 2023 DOE also introduced SEER2, EER2, and HSPF2 with updated testing conditions.
Frequently Asked Questions
What is a good SEER rating?
SEER 16–18 is the sweet spot for most homes. SEER 14–15 is the minimum (and cheapest). SEER 20+ is premium and best for hot climates with high electricity rates. The 2023 DOE minimum is SEER 15 (SEER2 14.3) for new central ACs.
What is the difference between SEER and SEER2?
SEER2 is the new DOE testing standard (effective 2023) that uses higher external static pressure, more realistic duct conditions. SEER2 ratings are about 4.5% lower than SEER. Example: SEER 15 ≈ SEER2 14.3.
How much does SEER affect electricity bills?
Each 1-point increase in SEER reduces electricity use by ~6–7%. Going from SEER 14 to SEER 20 saves about 30% on cooling costs. For a $100/month cooling bill, that's $30/month savings.
Is SEER 21 worth the extra cost?
In hot climates (Zone 1-2) with electricity >$0.15/kWh: usually yes, payback in 5–8 years. In moderate climates: SEER 16–18 is more cost-effective. Calculate payback: (higher unit cost) ÷ (annual savings) = years to break even.