SEER / SEER2 Energy Efficiency Calculator – Find Your Cooling Savings
Quickly compare energy use and annual costs between your current system and a higher-efficiency upgrade. See how much you could save in just seconds.
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SEER / SEER2 Energy Savings Calculator
Estimate annual kWh & cost (current vs new). Toggle Simple or Advanced for more accuracy.
Method & assumptions
- SEER vs SEER2: Both are seasonal efficiencies in BTU/Wh. For comparability we convert SEER2 to SEER-equivalent with a conservative factor of 0.95 (SEER ≈ SEER2 / 0.95). You can change the factor in code if needed.
- Simple mode: kWh = (Tons × 12,000 × Hours) ÷ (SEER × 1000).
- Advanced base load: If Direct Load provided, BTU/h = that value; else BTU/h = Tons × 12,000 × LoadFactor.
- Duct loss: Energy is scaled by 1/(1 − DuctLoss).
- Fan & standby: kWh_add = (FanW + StandbyW) × Hours / 1000.
- CDD estimator: If CDD provided, Hours ≈ CDD × 0.75 (editable constant). This is a rough regional proxy.
- This tool gives estimates; on-site Manual J/D/S and local utility rates will change results.
Your Estimated Savings
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Based on your inputs above. Actual results vary with weather, ductwork, and installation quality.
Quick Tips for Accurate Results
Set realistic values
- Cooling hours: 600–900 (cool), 900–1400 (warm), 1400–2000+ (hot).
- Rate: Use the $/kWh line from your utility bill.
- Load factor: Homes typically run at 0.7–0.9 (Advanced).
- Duct losses: Leaky/attic ducts can waste 5–20%+.
How to Read Your Results
kWh vs. Cost
kWh shows energy used. Annual cost = kWh × your rate. If your rate changes seasonally, try an average or re-run with a higher/lower rate.
Savings Percent
This is the share of your current cooling bill you may save with the new efficiency, assuming similar usage and conditions.
Why New ≠ Zero
Even high-efficiency systems consume energy. Duct leakage, fan power, run hours, and setpoints keep the meter spinning.
What Changes the Savings Most
High impact inputs
- Your electricity rate: Higher $/kWh ⇒ bigger $ savings for the same kWh reduction.
- Season length (hours): Longer seasons magnify differences between efficiencies.
- Old vs new efficiency: Larger gap (e.g., SEER 12 → SEER2 18) increases savings.
- Duct condition: Sealing/insulating ducts often adds more savings than SEER alone.
- Fan & standby watts: Hundreds of watts across many hours add surprising kWh.
Typical Upgrade Scenarios
Older Split System → Modern Inverter
Going from SEER ~10–13 to SEER2 ~17–20 can cut cooling kWh significantly, especially in warm climates with long run hours.
Package/Rooftop in Hot Regions
Check both EER (peak) and SEER/SEER2 (seasonal). Peak efficiency matters on hottest days when usage spikes.
Good Equipment, Poor Ducts
If ducts are leaky or uninsulated, fix them. A tight duct system makes the new equipment’s rating show up on your bill.
Keep Your Savings Year After Year
Simple maintenance
- Replace/clean filters on schedule to maintain airflow.
- Keep outdoor coils clear of debris; maintain clearance.
- Check thermostat schedules (raise setpoint when away).
- Seal obvious duct leaks; insulate attic/garage runs.
Smart habits
- Use ceiling fans to feel cooler at a higher setpoint.
- Close blinds on hot afternoons; reduce solar gain.
- Avoid oversized equipment; ask about proper sizing.
If Your Result Looks Wrong
Try these checks
- Confirm $ / kWh from your latest bill.
- Revisit hours (use the ranges above or CDD × 0.7–0.8).
- Increase duct loss if ducts run in hot attics/garages.
- Add realistic fan watts (e.g., 200–800 W) in Advanced mode.
- Ensure the new efficiency is higher than the current one.
Key Terms You’ll See
SEER
- Seasonal Energy Efficiency Ratio (BTU/Wh). Legacy seasonal rating.
SEER2
- Updated seasonal rating (2023+) with new test procedure.
EER
- Single hot-point efficiency. Useful in hot/dry or rooftop applications.
kWh
- Kilowatt-hour; the unit utilities use to bill electricity.
CDD
- Cooling Degree Days; a weather-based proxy for cooling demand.
Frequently Asked Questions
How accurate is this calculator?
It’s an estimate. Accuracy improves with realistic hours (or CDD), duct losses, and fan power. For precise design, ask for a Manual J/D/S evaluation.
Should I use SEER or SEER2?
SEER2 is the new standard. Compare SEER→SEER or SEER2→SEER2 for apples-to-apples results.
How do I pick cooling hours?
Use the climate ranges above or estimate from Cooling Degree Days (CDD × 0.7–0.8).
Why do ducts and fan power matter?
Leaky ducts and higher fan watts add significant kWh over a season. Sealing/insulating ducts and high-efficiency motors reduce waste.
Will a higher SEER always save money?
Usually, yes—but savings depend on climate, electricity rate, ductwork, sizing, and installation quality.