{ "slug": "heat-pump-vs-furnace", "title": "Heat Pump vs Furnace Operating Cost Calculator", "heading": "Heat Pump vs Gas Furnace Cost Calculator", "category": "financial", "url": "https://www.revenuelab.fyi/toolbox/heat-pump-vs-furnace", "summary": "Annual heating cost comparison by fuel type and efficiency.", "description": "Compares annual operating cost between an electric heat pump and a gas furnace using your climate's heating demand (in heating degree days or a simplified annual heating-load input), each system's efficiency rating (COP/HSPF2 for heat pumps, AFUE for furnaces), and your local energy prices. Heat pumps move heat rather than generate it, so their effective efficiency (coefficient of performance) is typically 200-350% even after derating for cold-climate performance, while furnaces top out around 95-98% AFUE. The crossover point depends heavily on the price ratio between electricity and gas in your area, which is why heat pumps are a clear win in the Pacific Northwest but a closer call in a state with cheap gas and expensive electricity.", "formula": "Furnace annual cost = heating load (therms) ÷ AFUE × gas price; heat pump annual cost = heating load (kWh equiv) ÷ COP × electricity price.", "dateModified": "2026-09-30", "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=heat-pump-vs-furnace", "inputs": [ { "id": "heatingLoad", "label": "Annual heating load", "kind": "number", "hint": null, "default": 60, "unit": "MMBtu", "min": 5, "max": null }, { "id": "afue", "label": "Furnace AFUE efficiency", "kind": "number", "hint": null, "default": 92, "unit": "%", "min": 60, "max": 99 }, { "id": "gasPrice", "label": "Natural gas price", "kind": "number", "hint": null, "default": 1.4, "unit": "$/therm", "min": 0.3, "max": 5 }, { "id": "cop", "label": "Heat pump seasonal COP", "kind": "number", "hint": null, "default": 2.8, "unit": null, "min": 1.5, "max": 4.5 }, { "id": "elecPrice", "label": "Electricity price", "kind": "number", "hint": null, "default": 0.15, "unit": "$/kWh", "min": 0.02, "max": 0.6 } ], "outputs": [ { "id": "heatPumpCost", "label": "Heat pump annual cost", "format": "currency", "hint": null, "primary": true }, { "id": "furnaceCost", "label": "Gas furnace annual cost", "format": "currency", "hint": null, "primary": false }, { "id": "annualSavings", "label": "Annual savings choosing the cheaper system", "format": "currency", "hint": null, "primary": false }, { "id": "cheaperOption", "label": "Cheaper to operate", "format": "raw", "hint": null, "primary": false } ], "worked_example": { "inputs": [ "Annual heating load: 60 MMBtu", "Furnace AFUE efficiency: 92 %", "Natural gas price: 1.4 $/therm", "Heat pump seasonal COP: 2.8", "Electricity price: 0.15 $/kWh" ], "outputs": [ "Heat pump annual cost: $942", "Gas furnace annual cost: $913", "Annual savings choosing the cheaper system: -$29", "Cheaper to operate: Furnace" ] }, "how_to": { "title": "How to use this", "steps": [ "Enter annual heating load (MMBtu).", "Enter furnace afue efficiency (%).", "Enter natural gas price ($/therm).", "Enter heat pump seasonal cop.", "Enter electricity price ($/kWh).", "Read your heat pump annual cost on the right — it updates as you type.", "Hit Share to keep the scenario or send it to someone." ] }, "scenarios": [ { "name": "Conservative", "description": "Lower-end numbers — what if things land soft?", "values": { "heatingLoad": 35, "afue": 60, "gasPrice": 0.84, "cop": 1.68, "elecPrice": 0.09 } }, { "name": "Typical", "description": "Defaults — the most common real-world setup.", "values": { "heatingLoad": 60, "afue": 92, "gasPrice": 1.4, "cop": 2.8, "elecPrice": 0.15 } }, { "name": "Ambitious", "description": "Higher-end numbers — what if things really pop?", "values": { "heatingLoad": 95, "afue": 99, "gasPrice": 2.2399999999999998, "cop": 4.4799999999999995, "elecPrice": 0.24 } } ], "limitations": [ "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.", "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.", "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant." ], "faq": [ { "q": "Where do I find my home's heating load?", "a": "Your gas bill's annual therm usage times roughly 100,000 Btu/therm gives a rough MMBtu total, or a Manual J load calculation from an HVAC contractor gives a precise design-day number you can scale to annual degree days. 40-80 MMBtu/year is typical for a mid-size US home depending on climate and insulation." }, { "q": "Why does COP drop in cold climates?", "a": "Standard heat pumps lose capacity and efficiency as outdoor temperature drops because there's less ambient heat to extract. Cold-climate heat pumps (using enhanced vapor injection compressors) maintain COP above 2 even at 5°F, while older or standard units may need electric-resistance backup heat below 20-25°F, which spikes the effective cost during a cold snap." }, { "q": "What COP number should I actually use?", "a": "Use the seasonal COP or HSPF2 rating divided by 3.412 to convert to COP, not the peak-condition COP on the spec sheet. A unit rated COP 4.0 at 47°F might average a seasonal COP of 2.5-3.0 across a full heating season in a mixed climate — using the peak number overstates savings." }, { "q": "Does this account for AC as a bonus with heat pumps?", "a": "No — this is heating cost only. A heat pump also provides cooling in summer, replacing a separate AC unit, which is a meaningful additional value not captured in a heating-only comparison and worth adding to your decision if you're currently paying for both a furnace and a separate AC system." } ], "related": [ "https://www.revenuelab.fyi/toolbox/mini-split-sizing", "https://www.revenuelab.fyi/toolbox/whole-home-load-calc", "https://www.revenuelab.fyi/toolbox/insulation-payback" ], "license": "CC-BY-4.0", "citation": "RevenueLab — Heat Pump vs Furnace Operating Cost Calculator (https://www.revenuelab.fyi/toolbox/heat-pump-vs-furnace)" }