How is annual cooling kWh calculated from SEER?

Annual kWh equals tons x 12,000 BTU/ton x equivalent full-load hours, divided by SEER, divided by 1,000. SEER is the seasonal BTU of cooling delivered per watt-hour of electricity, so dividing the seasonal BTU output by SEER gives watt-hours, which convert to kWh.

What are equivalent full-load cooling hours?

They are the number of hours the system would run at 100 percent capacity to meet the season's total cooling. A milder climate might be 600 to 1,000 hours; a hot, humid climate can exceed 2,000 to 2,500 hours. Use a local estimate for an accurate result.

Why use simple payback instead of full lifecycle cost?

Simple payback (extra equipment cost divided by annual savings) is a quick, transparent screen that customers understand. It ignores discount rates, rebates, maintenance, and fuel inflation, so treat it as a first-pass figure rather than a full financial model.

Should I use SEER or SEER2?

SEER2 is the newer test standard with higher external static pressure, so a SEER2 number is typically a few percent lower than the old SEER for the same unit. Compare like with like: use SEER for both units or SEER2 for both, not a mix, or your savings will be skewed.

Does this account for rebates?

Not directly, but you can subtract any utility or manufacturer rebate from the equipment cost difference before entering it. A lower net cost shortens the payback period proportionally.

SEER Energy Savings Calculator

The SEER energy savings calculator shows how much electricity and money a higher-efficiency air conditioner saves each cooling season, and how long it takes to pay back the price premium. It is the number that turns a premium-equipment quote into a justified investment for the customer.

How it works

Annual cooling energy depends on the seasonal cooling delivered and the unit’s SEER:

annual cooling BTU = tons x 12,000 x equivalent full-load hours
annual kWh         = annual cooling BTU / SEER / 1,000
annual cost        = annual kWh x electricity rate

savings  = old-unit cost - new-unit cost
payback  = equipment cost difference / annual savings

SEER is seasonal cooling output (BTU) per watt-hour of input, so dividing seasonal BTU by SEER gives watt-hours, which become kWh. A higher SEER produces the same cooling for fewer kWh, and the gap between the two units is the annual savings.

Example and tips

A 3-ton system running 1,200 equivalent full-load hours at $0.15/kWh uses 3 x 12,000 x 1,200 / 14 / 1,000 = 3,086 kWh per year at SEER 14, costing about $463. Upgrading to SEER 18 cuts that to 2,400 kWh and $360, saving roughly $103 per year. If the higher-SEER unit costs $1,500 more, simple payback is about 14.6 years. Use realistic local runtime hours; overstating them inflates the savings and shortens the payback unrealistically.