SEER energy savings calculator
Cooling capacity, hours of use per year, current and new SEER and electricity price: you get each unit's energy use and the annual savings.
Annual savings
300 kWh
- Annual savings300 kWh · £45.00
- Current annual use600 kWh
- Annual use with new unit300 kWh
Indicative estimate: £45.00
Your prices per language/currency. Used when you enable “Use my prices” in calculators. My prices →
How it's calculated (visible formula)
use = cooling capacity × hours ÷ SEER (W/W); savings = current − new; US SEER ≈ EU SEER × 3.41
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
How to calculate it, step by step
- Enter cooling capacity.
- Estimate equivalent full-load hours per year.
- Find current and new SEER (W/W).
- Use = cooling × hours ÷ SEER.
- Multiply the difference by your rate per kWh.
Worked example: 1-ton (3.5 kW) unit, 600 h/yr, SEER 12 → 24 (US), $0.15/kWh
- Cooling: 3.5 × 600 = 2,100 kWh
- SEER 12 ≈ 3.5 W/W → 600 kWh; SEER 24 ≈ 7 W/W → 300 kWh
→ 300 kWh saved: $45 a year.
Common mistakes
- Mixing US SEER (BTU/Wh) with EU SEER (W/W) — this tool uses W/W.
- Unrealistic full-load hours.
- Forgetting heating savings (HSPF).
Pro tips
- Convert US SEER/SEER2 to W/W by dividing by 3.41.
- Add heating savings with HSPF if you heat with it.
- Payback = cost ÷ annual savings.
- Clean filters keep real-world efficiency up.
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- What is a good SEER?
- In the US, SEER2 15–16+ is efficient; top units exceed 20.
- How do I convert US SEER to W/W?
- Divide by 3.41 (SEER 17 ≈ 5 W/W).
- What about heating?
- Repeat with HSPF ÷ 3.41 and winter hours.
- How much will I save replacing a 15-year-old AC?
- Often 30–50% of cooling energy.
- EER vs SEER?
- EER is one operating point; SEER weights the whole season.
- How many cooling hours per year?
- About 1,000–2,000 in hot US climates.
Sources and standards
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.