HVAC Operating Cost Calculator — Free Online Calculator
Every heating and cooling system turns energy into comfort at a price set by three things — its capacity, its efficiency rating, and your local energy cost. This tool converts those into the real cost to run your AC, heat pump, or furnace per hour, per day, and per year, so you can compare equipment honestly.
Comparing two specific units? Use the SEER Savings Calculator for cooling efficiency, or the AFUE Savings Calculator to pit two furnaces against each other.
Enter your system details
= 3.0 tons
SEER/HSPF for AC & heat pumps · AFUE % for gas.
Cooling season ≈ 90–150 · heating ≈ 120–180.
U.S. average ≈ $0.17/kWh
U.S. residential average ≈ $1.50–1.60/therm
Costs you to run
Per hour
$0.41
Per day
$3.26
Energy used per year
2,304 kWh
See the breakdown
Estimates assume the unit runs at rated efficiency; real bills vary with weather, thermostat habits, duct condition, and cycling.
What common systems cost to run
At the U.S. averages of $0.17/kWh and $1.50/therm. 3-ton (36,000 BTU) cooling/heat-pump, 80,000 BTU furnace, 10 kW electric. Per-day shown at 8 run-hours.
| System | Efficiency | Energy use | Cost / hour | Cost / day (8 hr) |
|---|---|---|---|---|
| Central AC (cooling) | SEER 14 | 2.57 kWh/hr | $0.44 | $3.50 |
| Central AC (cooling) | SEER 16 | 2.25 kWh/hr | $0.38 | $3.06 |
| Central AC (cooling) | SEER 20 | 1.80 kWh/hr | $0.31 | $2.45 |
| Heat pump (heating) | HSPF 8.5 | 4.24 kWh/hr | $0.72 | $5.76 |
| Heat pump (heating) | HSPF 10 | 3.60 kWh/hr | $0.61 | $4.90 |
| Gas furnace | 80% AFUE | 1.00 therm/hr | $1.50 | $12.00 |
| Gas furnace | 95% AFUE | 0.84 therm/hr | $1.26 | $10.11 |
| Electric furnace | 10 kW | 10.0 kWh/hr | $1.70 | $13.60 |
Estimates for comparison only. Actual usage varies with weather, home condition, and how you run your thermostat.
Sources & standards: U.S. EIA — Average residential electricity price (≈16.8¢/kWh, 2025); U.S. EIA — Residential natural gas prices (≈$16.25 per thousand cubic feet ≈ $1.55/therm); U.S. DOE Energy Saver — Furnaces & Heat Pumps (efficiency basics).
The formula, explained in plain English
Operating cost is just "energy used per hour × what that energy costs." How you get the energy per hour depends on whether the system burns gas or runs on electricity — here is exactly what this calculator does.
Higher SEER/HSPF = lower cost
Operating cost is inversely proportional to the efficiency number — double the SEER and you roughly halve the energy (and the bill) for the same cooling.
Why electric resistance is pricey
Resistance heat has a COP of 1.0 — every BTU costs a full BTU of electricity. A heat pump delivers 2–4 BTU of heat per BTU of electricity, so it runs for a fraction of the cost.
Gas vs electric
Compare $/therm to $/kWh on a per-BTU basis. Gas heat is usually cheaper per hour than electric resistance heat, though a heat pump can close or beat that gap.
Runtime is everything
A cheap-per-hour furnace run all winter can cost more than a pricier-per-hour AC run in short bursts. Hours per day × days per year drive the annual number.
Worked examples
Three common scenarios — cooling, two ways to heat, and a furnace efficiency upgrade.
Running a 3-ton AC in summer — SEER 15
36,000 BTU · 8 hr/day · 120 days · $0.17/kWh.
× $0.17 = $0.41/hr
at 8 hr/day × 120 days = 960 hr → $392/year
Result: about $0.41 an hour, $3.26 a day, and roughly $392 over a typical cooling season.
Heat pump vs electric furnace heating
Same 36,000 BTU of heat · $0.17/kWh.
electric strip (3,412): 36,000 ÷ 3,412 = 10.55 kWh/hr → $1.79/hr
→ the heat pump heats for ~38% of the cost
Result: resistance heat costs nearly 3× as much per hour because every BTU needs a full BTU of electricity.
80,000 BTU gas furnace — 80% vs 95% AFUE
80,000 BTU · $1.50/therm · ~1,000-hour heating season.
95%: 0.84 therm/hr → $1.26/hr
over 1,000 hr: $1,500 vs $1,263 → about $237 saved a year
Result: the higher-AFUE furnace burns ~16% less gas for the same heat — meaningful savings over a full heating season.
Frequently asked questions
Common questions about what it costs to run heating and cooling equipment.
How much does it cost to run an air conditioner per hour?
For a typical 3-ton, SEER 15 central AC at the U.S. average $0.17/kWh, about $0.41 per hour (2.4 kWh). Bigger or less efficient units cost more; the calculator above runs your exact numbers.
How much does it cost to run an AC per day / per month?
At ~$0.41/hr, running 8 hours a day is about $3.26/day, or roughly $98 a month. Hot-climate homes running 12+ hours a day pay proportionally more.
What's the formula for HVAC running cost?
For AC/heat pumps: kWh/hr = capacity BTU ÷ efficiency (SEER or HSPF) ÷ 1,000, then × your $/kWh. For gas: therms/hr = BTU ÷ (AFUE ÷ 100) ÷ 100,000, then × $/therm.
Is it cheaper to heat with a gas furnace or a heat pump?
It depends on local gas and electricity prices, but a heat pump delivers 2–4 units of heat per unit of electricity, so it usually beats electric resistance heat outright and is competitive with gas — especially in milder weather above its balance point.
Why is electric (resistance) furnace heat so expensive?
Resistance heat has a COP of 1.0: every BTU of heat needs a full BTU of electricity. A heat pump moves heat instead of making it, delivering several BTU per BTU of power, which is why it costs a fraction as much to run.
Does a higher SEER or HSPF really lower my bill?
Yes — operating cost is inversely proportional to the efficiency number. Going from SEER 14 to 20 cuts cooling energy about 30%. Compare two specific units with our SEER Savings and AFUE Savings calculators.
Why doesn't this match my utility bill exactly?
It assumes rated efficiency and steady runtime. Real bills vary with weather, thermostat settings, duct leakage, cycling losses, tiered rates, and fixed charges. Use this to compare equipment, not to predict a bill to the penny.
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