Why might my annual savings show as negative?

A negative savings number means the heat pump costs more to run for heating than a gas furnace under your assumptions—often because electricity is expensive relative to gas or the COP is low. Adjust COP and energy prices to reflect your actual situation, and consider non‑financial drivers like comfort or emissions.

How should I incorporate rebates, tax credits, or other incentives?

You can subtract incentives from the heat pump installed cost before entering it, or mentally reduce the heat pump premium when interpreting payback. This shortens the payback period and better reflects your real out‑of‑pocket cost.

Can this calculator handle hybrid or dual-fuel systems?

Not directly. The model assumes either a pure heat pump or a pure gas furnace for the heating load. For dual‑fuel setups, you can approximate by assigning part of your Heating hours to the heat pump and part to the furnace, and then combine the results.

Does this include cooling savings from a heat pump?

No. The calculator focuses on heating costs. In many climates, a heat pump can replace both a furnace and an air conditioner; any savings on cooling energy or avoided AC replacement costs should be evaluated separately.

How accurate is it to use a single COP value for the whole heating season?

Using a single COP is a simplification. Real‑world COP fluctuates as outdoor temperatures and operating conditions change. For a more accurate picture, use a seasonal COP estimate informed by performance curves or contractor/utility tools for your specific climate and equipment.

finance calculator

Heat Pump vs Gas Heat Cost Calculator

Compare annual heating costs for a heat pump vs a gas furnace using load, runtime, COP/efficiency, fuel prices, and see payback on the heat pump premium.

Results

Annual gas therms: 1000.00
Annual gas cost: $1,250
Annual kWh (heat pump): 8242.97
Annual electric cost: $1,154
Annual savings (heat pump vs gas): $96
Simple payback (years): 41.67

Overview

Heat pumps and gas furnaces both keep your home warm, but they use energy very differently. A modern heat pump can move several units of heat for every unit of electricity it consumes, while a gas furnace burns fuel directly and is limited by combustion efficiency. Whether a heat pump actually saves you money depends on your heating load, runtime, heat pump COP (coefficient of performance), furnace AFUE, and your local gas and electricity prices. This calculator lets you plug in those numbers to compare annual heating costs and see a simple payback period on any extra upfront cost of a heat pump compared with a gas furnace.

How to use this calculator

Enter your estimated Heating load (BTU/hr) from a Manual J, contractor estimate, or rule‑of‑thumb sizing, and Heating hours per year based on your climate and usage.
Enter an average Heat pump COP that reflects real‑world seasonal performance in your climate, not only lab ratings at mild temperatures.
Enter Furnace efficiency (AFUE, as a decimal), along with your current Gas price per therm and Electricity rate ($/kWh) from recent utility bills.
Provide rough installed costs for a heat pump system and a gas furnace sized for the same load. If you already own a furnace and are only adding a heat pump, focus on the incremental heat pump cost.
Review the calculated annual gas therms and cost, annual heat pump kWh and electric cost, annual savings, and payback period.
Adjust COP, AFUE, fuel prices, and installed costs to explore different what‑if scenarios—such as future price changes, different equipment options, or net costs after rebates and tax credits.

Inputs explained

Heating load (BTU/hr): Your home’s design heating load or system capacity in BTU per hour. This is typically determined by a Manual J load calculation or a contractor’s sizing estimate. It represents the amount of heat needed to keep your home comfortable at the design temperature.
Heating hours per year: An estimate of how many hours per year the heating system runs at or near the entered load. Colder climates will have more hours; milder climates fewer. It serves as a simple way to translate your load into annual energy use.
Heat pump COP: The average coefficient of performance (COP) of the heat pump over the heating season. COP is the ratio of heat delivered to electrical energy consumed. Higher COP means more efficient operation and lower kWh for the same load.
Furnace efficiency (AFUE): The gas furnace’s Annual Fuel Utilization Efficiency, entered as a decimal (for example, 0.9 for 90% efficiency). AFUE measures the fraction of fuel energy that becomes usable heat over the course of a season.
Gas price per therm: The price you pay per therm (100,000 BTU) of natural gas, taken from your gas bill or utility rate schedule. If your bill uses other units, convert to dollars per therm for consistency.
Electric rate ($/kWh): Your all‑in electricity price per kilowatt‑hour, including both energy and delivery charges. Using the effective rate from your bill makes the cost comparison more realistic.
Heat pump installed cost: The total installed cost of a heat pump system sized for your load, including equipment, labor, permits, and typical accessories. Subtract rebates and tax credits if you want payback to reflect net cost.
Gas furnace installed cost: The total installed cost of a gas furnace alternative. If you are replacing an existing furnace, use the cost of a new, comparable system. If the furnace already exists and you are not replacing it, the effective furnace cost for a marginal decision may be lower or even zero.

Outputs explained

Annual gas therms: The estimated number of therms of natural gas a furnace would burn each year to meet your heating load, after adjusting for furnace efficiency.
Annual gas cost: The annual cost of running a gas furnace, calculated by multiplying annual gas therms by your gas price per therm.
Annual kWh (heat pump): The estimated annual electrical energy consumption of a heat pump providing the same heating load, based on the COP and heating hours you entered.
Annual electric cost: The annual cost of running the heat pump for heating, found by multiplying annual kWh by your electricity rate.
Annual savings (heat pump vs gas): The difference between the gas furnace’s annual fuel cost and the heat pump’s annual electric cost. A positive number indicates annual savings from using a heat pump; a negative number indicates the heat pump costs more to run for heating.
Simple payback (years): An approximate payback period for the heat pump’s extra upfront cost, computed as the cost premium divided by annual savings. If annual savings are negative, payback is not meaningful.

How it works

The model starts with your Heating load in BTU/hr and your estimated Heating hours per year. Multiplying them gives an approximate annual heating demand in BTU: Annual load ≈ Load × Hours. This represents the amount of heat your home needs in a year at the design capacity you entered.

For a gas furnace, the delivered heat must come from burning natural gas. One therm equals 100,000 BTU of fuel input. Because a furnace is not perfectly efficient, the calculator divides by the furnace efficiency (AFUE) to find fuel input: Gas therms ≈ (Load × Hours ÷ 100,000) ÷ AFUE.

Annual gas cost is then Gas cost annual ≈ Gas therms × Gas price per therm, using the price you enter from your gas bill or rate schedule.

For a heat pump, the key variable is COP (coefficient of performance). COP describes how much heat is delivered per unit of electrical energy. To deliver the same heating load, the electrical input in BTU/hr is Load ÷ COP. Converting BTU/hr to kilowatts uses 3,412 BTU/hr per kW: Heat pump kW ≈ (Load ÷ COP) ÷ 3,412.

Annual electrical use is Electric kWh annual ≈ Heat pump kW × Heating hours. The annual electric heating cost is Heat pump cost annual ≈ Electric kWh annual × Electricity rate ($/kWh).

Annual savings from using a heat pump instead of a gas furnace for heating is Annual savings ≈ Gas cost annual − Heat pump cost annual. A positive value means the heat pump is cheaper to run; a negative value means gas is cheaper under your assumptions.

To compare equipment economics, the calculator looks at Heat pump installed cost and Gas furnace installed cost. The extra upfront investment in a heat pump is Heat pump premium ≈ Heat pump cost − Furnace cost.

Simple payback is then Payback years ≈ Heat pump premium ÷ Annual savings. This tells you how many years of operating savings it would take for the extra upfront cost of the heat pump to “pay for itself,” ignoring financing, tax credits, and the time value of money.

Formula

Annual load (BTU) ≈ Heating load (BTU/hr) × Heating hours
Gas therms ≈ (Annual load ÷ 100,000) ÷ AFUE
Annual gas cost ≈ Gas therms × Gas price per therm
Heat pump kW ≈ (Heating load ÷ COP) ÷ 3,412
Annual kWh ≈ Heat pump kW × Heating hours
Annual electric cost ≈ Annual kWh × Electricity rate
Annual savings ≈ Annual gas cost − Annual electric cost
Heat pump premium ≈ Heat pump installed cost − Gas furnace installed cost
Simple payback (years) ≈ Heat pump premium ÷ Annual savings

When to use it

Deciding whether to install a heat pump instead of a gas furnace during new construction or a major HVAC replacement, based on your local energy prices.
Estimating the payback period for electrifying your home’s heating system, using realistic COP and AFUE values and net installed costs after rebates.
Comparing different equipment options—such as higher‑efficiency furnaces or variable‑speed heat pumps—by adjusting COP and AFUE to see how they affect annual costs.
Exploring how changes in gas and electricity prices would shift the economics of heat pumps versus gas heating over time.
Providing a grounded starting point for discussions with HVAC contractors and utilities about heat pump incentives, dual‑fuel strategies, and long‑term operating costs.

Tips & cautions

Use seasonal COP values that reflect your climate, not just manufacturer ratings at mild temperatures. Contractors or utilities may have modeled seasonal performance data for your region.
Energy prices matter as much as equipment efficiency. In areas with very cheap gas and expensive electricity, heat pumps may not currently save money on heating alone—even if they are very efficient.
If you keep a gas furnace as backup (dual‑fuel), consider splitting your Heating hours between the heat pump and furnace or modeling only the portion of the load you expect the heat pump to cover.
Remember that heat pumps also provide cooling. When comparing overall value, factor in the avoided cost of a separate air conditioner and the heat pump’s cooling efficiency.
Apply rebates, tax credits, and other incentives to the heat pump installed cost to see a more realistic payback period. In many regions, incentives significantly improve heat pump economics.
The calculator models only heating energy. Cooling performance, dehumidification, and seasonal comfort differences are not included.
COP and AFUE are treated as fixed values and do not vary by outdoor temperature, part‑load operation, or duct losses, all of which affect real‑world performance.
Simple payback ignores the time value of money, financing costs, tax treatment, maintenance differences, and equipment lifespan. A more detailed financial analysis may be appropriate for large investments.
The model assumes your heating load estimate and runtime hours are reasonably accurate. Large errors in these inputs will produce misleading results.
Results are approximate and meant for planning and education, not for making final equipment decisions without consulting qualified professionals and verifying local energy rates and incentives.

Worked examples

60k BTU load, 1,500 hours, COP 3.2, 90% AFUE, $1.25/therm, $0.14/kWh, $9,500 heat pump, $5,500 furnace

Annual load ≈ 60,000 × 1,500 = 90,000,000 BTU.
Gas therms ≈ (90,000,000 ÷ 100,000) ÷ 0.90 ≈ 1,000 therms; Annual gas cost ≈ 1,000 × $1.25 = $1,250.
Heat pump kW ≈ (60,000 ÷ 3.2) ÷ 3,412 ≈ 5.49 kW; Annual kWh ≈ 5.49 × 1,500 ≈ 8,235 kWh.
Annual electric cost ≈ 8,235 × $0.14 ≈ $1,153; Annual savings ≈ $1,250 − $1,153 ≈ $97 in favor of the heat pump.
Heat pump premium ≈ $9,500 − $5,500 = $4,000; Simple payback ≈ $4,000 ÷ $97 ≈ 41 years, indicating limited economic benefit on heating alone at these rates.

50k BTU load, 1,800 hours, COP 4.0, 80% AFUE, $1.80/therm, $0.10/kWh, $10,000 heat pump, $6,000 furnace

Annual load ≈ 50,000 × 1,800 = 90,000,000 BTU.
Gas therms ≈ (90,000,000 ÷ 100,000) ÷ 0.80 ≈ 1,125 therms; Annual gas cost ≈ 1,125 × $1.80 ≈ $2,025.
Heat pump kW ≈ (50,000 ÷ 4.0) ÷ 3,412 ≈ 3.66 kW; Annual kWh ≈ 3.66 × 1,800 ≈ 6,588 kWh.
Annual electric cost ≈ 6,588 × $0.10 ≈ $659; Annual savings ≈ $2,025 − $659 ≈ $1,366.
Heat pump premium ≈ $10,000 − $6,000 = $4,000; Simple payback ≈ $4,000 ÷ $1,366 ≈ 2.9 years, suggesting strong economics for a heat pump in this scenario.

Deep dive

This heat pump vs gas heat cost calculator compares annual heating costs using your heating load, runtime, heat pump COP, furnace AFUE, and local gas and electricity prices, then estimates a simple payback on any extra heat pump upfront cost.

Use it as a starting point for deciding whether electrifying your heating with a heat pump makes financial sense where you live and for preparing questions for HVAC contractors and utility programs.

FAQs

Why might my annual savings show as negative?: A negative savings number means the heat pump costs more to run for heating than a gas furnace under your assumptions—often because electricity is expensive relative to gas or the COP is low. Adjust COP and energy prices to reflect your actual situation, and consider non‑financial drivers like comfort or emissions.
How should I incorporate rebates, tax credits, or other incentives?: You can subtract incentives from the heat pump installed cost before entering it, or mentally reduce the heat pump premium when interpreting payback. This shortens the payback period and better reflects your real out‑of‑pocket cost.
Can this calculator handle hybrid or dual-fuel systems?: Not directly. The model assumes either a pure heat pump or a pure gas furnace for the heating load. For dual‑fuel setups, you can approximate by assigning part of your Heating hours to the heat pump and part to the furnace, and then combine the results.
Does this include cooling savings from a heat pump?: No. The calculator focuses on heating costs. In many climates, a heat pump can replace both a furnace and an air conditioner; any savings on cooling energy or avoided AC replacement costs should be evaluated separately.
How accurate is it to use a single COP value for the whole heating season?: Using a single COP is a simplification. Real‑world COP fluctuates as outdoor temperatures and operating conditions change. For a more accurate picture, use a seasonal COP estimate informed by performance curves or contractor/utility tools for your specific climate and equipment.

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This heat pump vs gas heat cost calculator is an educational tool that uses simplified assumptions about heating load, operating hours, equipment efficiency, and energy prices. It does not replace a Manual J load calculation, detailed energy modeling, or professional financial advice. Always confirm system sizing and performance with licensed HVAC professionals and verify current gas and electricity rates and incentives with your utility providers before committing to major equipment purchases or electrification projects.