Free AC running-cost calculator
AC Operating Cost Calculator: Monthly Cooling Cost
Enter your system size, efficiency rating, and how hard it runs, and the calculator estimates the month's cooling electricity — and the cost, once you add your own rate from your utility bill.
Quick answer: How much does it cost to run AC per month? A 3-ton system at 15.2 SEER2 running the equivalent of 10 full-load hours a day for a 30-day month uses about 711 kWh of cooling electricity. At around $0.15 per kWh that is roughly $107 for the month — your electric rate and the system's runtime move the number most.
How much does it cost to run AC per month?
Utility rates change and vary by plan. Around $0.15 per kWh is typical in the Tampa Bay area — confirm yours with your utility bill. The calculator never guesses a rate: leave it blank for kWh only, or enter the exact figure from your bill.
How this calculator works
Monthly kWh = tons × 12,000 BTU/hr × equivalent full-load hours per day × days ÷ SEER2 ÷ 1,000. Cost = kWh × your electric rate. Equivalent full-load hours count only the time the compressor would run at 100% output — not wall-clock hours — because a properly sized system cycles.
Pinellas County context
Pinellas County cooling seasons are long: the sizing guide on this site estimates 2,000–3,000 equivalent full-load cooling hours per year in this area, most of them May through October.
Frequently asked questions
How many kWh does AC use per month in Florida?
It depends on size, efficiency, and runtime. Using the calculator's defaults — a 3-ton, 15.2 SEER2 system running the equivalent of 10 full-load hours a day for 30 days — that is about 711 kWh of cooling electricity for the month. A larger, older, or harder-working system uses more; a right-sized or higher-SEER2 system uses less.
Why does the calculator ask for equivalent full-load hours instead of runtime hours?
Because a central AC cycles: it runs at full output only part of the time it is switched on. Equivalent full-load hours express how much full-capacity work the system actually did. Around 10 equivalent full-load hours is typical on a hot Pinellas County August day; shoulder-season days are far lower.
What SEER2 rating should I enter?
Use the SEER2 rating printed on your outdoor unit's nameplate or in your system documentation. In the Southeast region, which includes Florida, new split-system central ACs under 45,000 BTU/h must meet a 14.3 SEER2 minimum, and systems rated at 45,000 BTU/h and above must meet 13.8 SEER2. Systems installed before 2023 can be well below those minimums.
How can I lower my monthly AC operating cost?
The biggest levers are maintenance (a dirty coil or clogged filter makes the system run longer), a higher-SEER2 system at replacement time, a smart thermostat schedule, sealed ducts, and adequate attic insulation. Comfort Club maintenance keeps a system running closer to its rated efficiency.
Does this include fan and air handler electricity?
The estimate covers the cooling system's rated efficiency at full load. A blower fan — especially a constant fan left ON — adds usage on top of the estimate, as does a heat pump's auxiliary heat in winter. Treat the result as the cooling-season compressor share of your bill.