How Much Electricity Does Air Conditioning Use?

Air-conditioner capacity is measured in tons — a legacy unit from the days of cooling with ice. One ton equals 12,000 BTU/h of cooling. Typical homes use 2-ton (24,000 BTU), 3-ton (36,000 BTU), 4-ton (48,000 BTU), or 5-ton (60,000 BTU) systems.

Electrical draw is a different question. As a rough planning heuristic, a central AC pulls about 1,000–1,200 watts per ton at full load — so a 3-ton system runs on the order of 3,000–3,500 watts. But wattage is not a fixed property of tonnage. It changes with the unit’s efficiency (EER2), the outdoor and indoor temperature, the blower, duct static pressure, and whether the compressor is single-stage or variable-speed. Treat any single number as an approximation.

The most defensible way to estimate full-load power is watts ≈ BTU/h ÷ EER2 at design conditions. For a 3-ton unit at EER2 12: 36,000 ÷ 12 ≈ 3,000 W. The calculator below uses this method.

SEER (Seasonal Energy Efficiency Ratio) measures seasonal cooling output per unit of energy — higher is more efficient. On January 1, 2023, SEER2 replaced it, using a more realistic test (higher external static pressure). SEER and SEER2 are based on different test procedures and should not be treated as directly interchangeable — use the manufacturer’s certified SEER2 rating.

California is in the U.S. Department of Energy’s Southwest region (with AZ, NV, NM), which has stricter minimums than the national baseline. For split-system central ACs installed on or after January 1, 2023:

Units below the SEER2 minimum cannot be installed in the Southwest region after that date.

Source: U.S. DOE regional efficiency standards · verified August 4, 2026.

The math is simple: kWh = watts ÷ 1,000 × hours, then cost = kWh × rate. The table below assumes the EER2 12 watt figures from the calculator and shows how much the rate period changes the result. Rates are illustrative 2026 examples, before any baseline credit.

The takeaway: running a 3-ton AC for five hours during SCE’s 4–9 p.m. peak can cost roughly twice what the same hours cost off-peak. Over a hot month, that difference alone can be well over $100. These are illustrative Cali Energy calculations from the stated assumptions, not measured bills.

Rate sources (before baseline credit): SCE Time-of-Use plans · LADWP residential rates · verified August 4, 2026.

California’s building climate zones capture how much cooling a home actually needs. In the Los Angeles area:

The gap is large: SCE customers in a hot climate zone average markedly more electricity than those in a cool coastal zone, and most of that difference is air conditioning.

A heat pump is essentially an air conditioner that can also run in reverse to heat. Its cooling efficiency uses the same SEER2 metric, so for cooling a heat pump and a straight AC of the same SEER2 use the same electricity. The heat pump’s advantage is on the heating side, where a COP of 3–4 means it delivers three to four units of heat per unit of electricity — far more efficient than electric-resistance heat. California’s 2025 Energy Code (effective January 1, 2026) makes heat pumps the prescriptive baseline for space and water heating in new construction.

Source: CEC 2025 Building Energy Efficiency Standards · verified August 4, 2026.

Rebates can offset the cost of a more efficient system. As of August 4, 2026, in Cali Energy’s review of the official programs:

• LADWP Consumer Rebate Program: up to $2,500 per ton for qualifying heat-pump HVAC. The temporary higher rebate applies to eligible equipment purchased and installed June 1–September 30, 2026, with applications due by December 31, 2026; amounts depend on SEER2/HSPF2 and other program requirements (baseline 15.2 SEER2 / 7.7 HSPF2, top tier 20.5 SEER2 / 9.1 HSPF2). The program also lists standard central AC at $100–120 per ton, heat-pump water heaters up to $2,500, and a $140 smart-thermostat rebate that can stack on the same project.
• SCE: a $75 smart-thermostat enrollment credit, the Energy Savings Assistance Program (free HVAC upgrades for income-qualified households), and TECH Clean California heat-pump incentives.

Every rebate amount is subject to eligibility, approved equipment, funding availability, installation date, and program rules, and is not guaranteed until approved by the program administrator. Do not treat a rebate as part of a system’s final cost before it is approved — funding is often first-come, first-served and can run out.

Source: LADWP Consumer Rebate Program · verified August 4, 2026.

AC demand peaks on hot, sunny afternoons — roughly when solar production peaks — so solar naturally offsets a lot of daytime cooling. The expensive hours are SCE’s 4–9 p.m. peak, after solar output falls, which is where a battery helps: charged midday, a properly sized battery system may support some or all AC operation during peak hours, avoiding 58–74¢/kWh electricity.

Whether a given battery can actually carry an AC depends on the compressor’s starting (locked-rotor) current, the inverter’s continuous power output, battery capacity, a soft-starter, and other simultaneous loads — a small battery may not even start a large single-stage compressor. On LADWP’s flat retail net metering the arbitrage case is weaker (every solar kWh already offsets full retail); under SCE’s Net Billing Tariff, shifting AC load to a battery is where the savings are. See our guides on battery sizing and whole-home vs critical-loads backup.

A note on comfort and safety: do not reduce cooling in a way that jeopardizes health or required indoor conditions. The cost examples here are informational, not personal safety guidance.

Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified August 4, 2026.

1. DOE / ENERGY STAR — central AC SEER2 requirements
2. LADWP — Consumer Rebate Program
3. SCE — Rebates & Marketplace
4. CEC — Building Climate Zones