Heat pump vs gas furnace cost calculator

Compare a gas furnace with a heat pump delivering the same yearly heat. Start with gas used for heating alone. Leave out gas for cooking, water heating or other uses. Use your bills and an installer assessment to separate these amounts if needed.

Enter furnace efficiency, the gas price per therm and yearly fixed gas charges. A therm measures gas energy. If your bill uses Ccf or Mcf, ask the supplier for the matching therm conversion before entering it. Do not treat a volume of gas as the same number of therms.

Enter a lower and higher assessed seasonal COP for the proposed heat pump. These are two performance scenarios, not promises about your home. Decide whether the gas account stays open. Add the net installed changeover quote and any extra yearly heat pump maintenance to compare running costs and simple payback.

Useful heat = heating-only fuel use × fuel energy content × existing seasonal efficiency. Heat pump electricity = useful heat ÷ assessed seasonal COP. Add only the fixed fuel charges that remain. Payback uses net installed price and positive annual savings after extra maintenance.

COP means coefficient of performance: heat delivered divided by electricity used. A seasonal COP of 3 means 3 kWh of heat for each 1 kWh of electricity across the assessed season. Use the ratio itself. Convert furnace efficiency from a percentage once; 90% means 0.90.

The higher COP gives the lower electricity use and cost. Electricity prices in cents per kWh are divided by 100 to get dollars; the gas price is already in dollars per therm. The result separates fuel, retained fixed charges and extra maintenance, then compares both heat pump costs with the current furnace.

These illustrative inputs are separate from your saved answers. Prices, use and performance are held constant for this worked scenario; they are not personal defaults.

Use seasonal whole-system performance that includes defrost and backup heating in the electricity input. A maker's COP at one outdoor temperature cannot by itself describe a full heating season. The calculator does not choose a climate curve or model a hybrid system's switching schedule.

Fixed gas charges disappear only if that account and those costs actually end. Keep them when other gas appliances remain. Existing electricity account charges are outside this comparison. The furnace's extra electrical use is not added automatically.

Simple payback divides the entered net installed cost by a positive annual saving after extra maintenance. Zero or negative savings have no finite payback. This keeps prices, demand and performance constant and leaves out borrowing costs, replacement and future price changes. Average monthly costs are annual totals divided by twelve; they do not predict a winter bill.

Use efficiency evidence for your existing furnace, not an assumed value for every gas system. Ask the installer to explain any difference between its rating and the seasonal figure used in the comparison.

The published electricity option uses EIA state residential averages for July 2026, released on 24 September 2026 and checked on 14 October 2026. These describe past average prices. They are not your supplier's offer or a promise of future prices. Choose your bill price for a personal comparison. Include the taxes and usage charges that change with consumption; keep fixed account charges separate.

Ask a qualified heating contractor to assess heating demand, furnace efficiency and the proposed heat pump's seasonal performance. Bring heating-only gas records and ask how backup heat is included in both COP scenarios.

Before changing systems, confirm equipment capacity, electrical supply, duct suitability and all changeover work in the quote. Ask which gas costs can actually end. The calculator cannot confirm safe installation or that either system will keep every room at the temperature you need.