Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Monthly running cost
$163.20
Daily cost
$5.44
5-month season cost
$816.00
Cost per runtime hour
$0.680
Energy units used per day
32.00
Annualized cost at this usage
$1,958.40
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter system capacity (BTU/hr).
- 2Enter system type.
- 3Enter efficiency rating (seer/hspf/afue %).
- 4Enter runtime hours per day.
- 5Enter days per month.
- 6Enter electricity rate ($/kWh).
- 7Enter gas rate ($/therm).
- 8Read your monthly running cost on the right — it updates as you type.
- 9Hit Share to keep the scenario or send it to someone.
About this calculator
A heat pump moving heat instead of making it can deliver three units of warmth per unit of electricity, which is why COP and SEER ratings dominate operating cost.
Worked example
Using the values the calculator loads with:
Inputs
- System capacity: 36000 BTU/hr
- System type: Heat pump (HSPF)
- Efficiency rating (SEER/HSPF/AFUE %): 9
- Runtime hours per day: 8
- Days per month: 30
- Electricity rate: 0.17 $/kWh
- Gas rate: 1.4 $/therm
Results
- Monthly running cost: $163.20
- Daily cost: $5.44
- 5-month season cost: $816.00
- Cost per runtime hour: $0.68
- Energy units used per day: 32
- Annualized cost at this usage: $1,958.40
What each field means
Inputs
- System capacity (BTU/hr)
- The system capacity used in the calculation, measured in BTU/hr. Starts at 36000 BTU/hr so you have a working example on load. Accepted range: 5000–200000 BTU/hr.
- System type
- Pick the option that matches your situation — the maths changes per option. Choices: Central AC (SEER), Heat pump (HSPF), Electric resistance, Gas furnace (AFUE).
- Efficiency rating (SEER/HSPF/AFUE %)
- The efficiency rating (seer/hspf/afue %) used in the calculation. Starts at 9 so you have a working example on load. Accepted range: 1–30.
- Runtime hours per day
- The runtime hours per day used in the calculation. Starts at 8 so you have a working example on load. Accepted range: 0–24.
- Days per month
- The days per month used in the calculation. Starts at 30 so you have a working example on load. Accepted range: 1–31.
- Electricity rate ($/kWh)
- The electricity rate used in the calculation, measured in $/kWh. Starts at 0.17 $/kWh so you have a working example on load. Accepted range: 0.01–1 $/kWh.
- Gas rate ($/therm)
- The gas rate used in the calculation, measured in $/therm. Starts at 1.4 $/therm so you have a working example on load. Accepted range: 0.2–6 $/therm.
Results
- Monthly running cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Daily cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 5-month season cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per runtime hour
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Energy units used per day
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annualized cost at this usage
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the hvac running cost calculator work?
A heat pump moving heat instead of making it can deliver three units of warmth per unit of electricity, which is why COP and SEER ratings dominate operating cost. The underlying maths is: Cost = BTU load ÷ efficiency rating × hours × energy price.
What do I need to enter?
7 values: system capacity, system type, efficiency rating (seer/hspf/afue %), runtime hours per day, days per month, electricity rate, and gas rate. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the monthly running cost result mean?
It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Heating & Cooling Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/hvac-run-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/hvac-run-cost" target="_blank" rel="noopener">Heating & Cooling Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Heating & Cooling Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/hvac-run-cost) (2026).