Use the calculator below to compare any two SEER or SEER2 ratings instantly. Enter your system details—capacity, electricity rate, annual cooling hours, and the price difference between units—and get your exact annual energy savings, percentage improvement, and payback period in seconds.
Whether you're comparing a 14.3 SEER2 baseline unit against a 15.2 SEER2 ENERGY STAR system, or deciding between 16 SEER2 and 20 SEER2, this calculator does the math for you.
The SEER2 Comparison Calculator
Enter your two SEER2 ratings (or legacy SEER ratings — see conversion table below) and your local conditions:
How the Calculator Works
The calculator uses a straightforward energy consumption formula based on DOE methodology:
Step 1: Annual Energy Use (kWh)
For each system:
kWh = (BTU capacity × annual cooling hours) ÷ (SEER2 rating × 1,000)
Example for a 3-ton (36,000 BTU) system at 15.2 SEER2 with 1,400 cooling hours:
kWh = (36,000 × 1,400) ÷ (15.2 × 1,000) = 50,400,000 ÷ 15,200 = 3,316 kWh
Step 2: Annual Cost
Annual cost = kWh × electricity rate ($/kWh)
Example: 3,316 kWh × $0.16 = $530.52/year
Step 3: Savings
Savings = Cost of lower-rated system − Cost of higher-rated system
Step 4: Payback Period
Simple payback = Price premium ÷ Annual savings
This calculator uses a "simple payback" method that doesn't account for electricity rate increases, inflation, or the time value of money. In reality, electricity rates have been rising 2–3% annually, which means your actual savings grow each year and the true payback is somewhat shorter than calculated. For a more conservative estimate, this simple method is appropriate.
SEER to SEER2 Conversion Table
If your contractor provided a legacy SEER rating, convert it to SEER2 before using the calculator:
Conversion formula: SEER2 ≈ SEER × 0.95 (±1–2% depending on equipment design)
Reverse formula: SEER ≈ SEER2 × 1.053
These are approximations. The exact SEER2 for any specific unit depends on its design characteristics. Always check the AHRI-certified rating for your exact model combination (outdoor unit + indoor coil) at ahridirectory.org.
Input Guide: Finding Your Numbers
How to Determine Your Cooling Hours
Your annual cooling hours depend primarily on your climate zone. Use this table as a starting point:
How to Find Your Electricity Rate
Check your most recent electric bill. Look for the rate per kWh—it may be listed as "energy charge" or "supply rate." Here are 2026 averages by state for reference:
Many utilities have tiered pricing or time-of-use rates. For the most accurate calculation, use your effective average rate during summer months (June–September), as that's when your AC runs most. Summer rates are often 10–30% higher than annual averages due to demand charges and seasonal pricing.
How to Determine System Capacity
Your system capacity is measured in tons or BTU/hour:
- 1 ton = 12,000 BTU/hour
- Most residential systems range from 1.5 to 5 tons
Find your tonnage on the outdoor unit's nameplate, in your installation paperwork, or by looking at the model number—many brands encode tonnage in the model number (e.g., "036" = 36,000 BTU = 3 tons).
Home size is only a rough guide. Actual cooling load depends on insulation, window area, orientation, shade, local climate, and more. A proper Manual J load calculation from a qualified HVAC contractor is the only accurate way to determine correct sizing.
Popular Comparison Scenarios (Pre-Calculated)
Scenario 1: 14.0 SEER2 vs 15.2 SEER2 (Federal Min North vs ENERGY STAR)
Scenario 2: 15.0 SEER2 vs 15.2 SEER2 (South Min vs ENERGY STAR)
Scenario 3: 15.2 SEER2 vs 17.0 SEER2 (ENERGY STAR vs High Efficiency)
Scenario 4: 15.2 SEER2 vs 19.0 SEER2 (ENERGY STAR vs Premium)
Scenario 5: 19.0 SEER2 vs 22.0 SEER2 (Premium vs Ultra-Premium)
Understanding the Results
What the Percentage Savings Means
The percentage savings applies to your cooling energy only, not your entire electric bill. Cooling typically represents:
- 40–60% of summer electricity use in hot climates
- 25–40% in moderate climates
- 10–25% in cold climates
- 20–35% of annual electricity use nationally
So a 20% reduction in cooling energy might translate to only a 4–12% reduction in your total annual electric bill.
Why Payback Periods Are Long
Three factors make SEER upgrade payback periods longer than people expect:
-
Electricity is relatively cheap. At $0.16/kWh, even significant kWh savings don't translate to large dollar amounts.
-
Cooling is seasonal. Unlike heating (which runs 5–8 months in cold climates), AC only runs 3–6 months, limiting annual savings.
-
Higher SEER costs exponentially more. Going from 14 to 16 SEER adds 2 SEER points for $1,000. Going from 16 to 20 adds 4 points for $4,000—the cost per SEER point doubles.
When the Calculator Underestimates Savings
The calculator may underestimate your real savings if:
- Your electricity rate is a summer peak rate (higher than annual average)
- You have time-of-use pricing where AC runs during expensive peak hours
- Electricity rates rise faster than the 2–3% annual average
- You're switching from a degraded old system (actual efficiency lower than rated)
- You're adding a heat pump that provides year-round savings (not just cooling)
Key Takeaways
- Use SEER2 ratings for all comparisons — they're the current standard and more accurate to real-world performance
- Convert legacy SEER to SEER2 by multiplying by 0.95 before comparing
- Small SEER2 differences (0.5–1.0 points) rarely matter financially — focus on features, price, and installation quality
- Large SEER2 jumps (3+ points) save meaningful energy but cost so much more that payback is often 20+ years
- The ENERGY STAR threshold (15.2 SEER2) is the critical cutoff — it unlocks $600+ in tax credits that often outweigh the equipment premium
- Your electricity rate is the biggest payback multiplier — homeowners paying $0.25+/kWh see 50–170% higher dollar savings
- Always factor in incentives — tax credits and utility rebates can cut payback by 50–90%
Frequently Asked Questions
Sources
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