Gas furnaces burn natural gas to heat your home, but electricity still powers several essential components. The amount of electricity a gas furnace uses each month depends on factors such as climate, furnace type, blower motor efficiency, and thermostat settings. While gas cost dominates winter bills, understanding monthly electricity use helps estimate total energy costs and identify savings. This guide explains typical electricity consumption, factors that influence it, and practical tips to estimate and reduce monthly electricity expenses without sacrificing comfort.
How Gas Furnaces Use Electricity
Electricity fuels air movement and ignition systems in a gas furnace. The blower motor pushes heated air through ducts, the induced-draft or exhaust blower removes combustion gases, and electronic controls, displays, and thermostats coordinate operation. Older furnaces commonly use a PSC (permanent split capacitor) blower that draws more power, while newer units may use an ECM (electronically commutated motor) that adjusts speed to save energy. Overall, electricity use is typically a small portion of the heating bill compared to natural gas.
Key Electrical Components
- Blower Motor — PSC or ECM. The blower circulates air and can account for the largest portion of electricity use.
- Induced-Draft/Exhaust Blower — Moves combustion gases out of the furnace and usually runs only during heat calls.
- Electronic Ignition and Control Board — Powers ignition, safety interlocks, and sequencing of operations.
- Thermostat and System Circuits — Senses temperature and controls when the furnace should heat or circulate air.
- Condensate Pump and Optional Humidifier — May draw additional power if installed and active.
- Standby Power for Controls — Small, continuous draw even when the furnace isn’t actively heating.
Estimating Monthly Electricity Use
To estimate monthly electricity use, identify the wattage of the main electrical components and estimate how many hours the furnace runs during the month. Include both active operation during heating calls and continuous standby power. Multiply wattage by hours to obtain kilowatt-hours (kWh), then multiply by your local electricity rate to estimate cost.
Steps To Estimate Your Use
- Find wattage data for your furnace’s major components (blowers, draft fan, controls) from the nameplate or manufacturer specs.
- Determine whether the blower is PSC (higher draw) or ECM (variable, usually lower average draw).
- Estimate hours of operation for the month based on climate and thermostat settings. Include hours of blower activity during heat calls and standby hours.
- Calculate energy use: kWh = Wattage (kW) × Hours. Sum for all components, including standby.
- Convert to cost: monthly cost = total kWh × price per kWh (local rate).
Sample Scenarios
Scenario A — PSC Blower in a Cold Climate Blower: 0.375 kW; Induced-draft: 0.12 kW; Standby: 0.005 kW. Assumed monthly operation: 6 hours per day for 30 days.
Blower energy: 0.375 × 6 × 30 = 67.5 kWh. Draft energy: 0.12 × 6 × 30 = 21.6 kWh. Standby energy: 0.005 × 24 × 30 = 3.6 kWh. Total: 92.7 kWh per month. At $0.14/kWh, estimated electricity cost: about $12.98 per month.
Scenario B — ECM Blower in Moderate Climate Blower: 0.15 kW; Induced-draft: 0.08 kW; Standby: 0.005 kW. Assumed monthly operation: 6 hours per day for 30 days.
Blower energy: 0.15 × 6 × 30 = 27 kWh. Draft energy: 0.08 × 6 × 30 = 14.4 kWh. Standby energy: 0.005 × 24 × 30 = 3.6 kWh. Total: 44.999 kWh per month. At $0.14/kWh, estimated electricity cost: about $6.30 per month.
These scenarios illustrate how blower type and climate affect monthly electricity use. Real-world numbers will vary based on furnace efficiency, duct design, and how often the thermostat calls for heat.
Factors Affecting Electricity Consumption
Several variables influence how much electricity a gas furnace uses each month. Understanding these factors helps homeowners estimate consumption more accurately and identify savings opportunities.
Climate and Heating Load
Colder regions with longer heating seasons generally require more furnace operation and, consequently, more electricity for the blower and draft systems. Warmer climates reduce monthly electrical use.
Blower Motor Type and Efficiency
ECM blowers adapt to heating demand and typically use significantly less electricity than PSC motors, especially at lower speeds. An ECM can substantially lower monthly kWh, particularly in homes with long runtimes or frequent cycling.
Air Distribution and Duct Efficiency
Leaks, poorly sealed ducts, or restricted airflow increase blower workload, boosting electricity use. Proper duct sealing, insulation, and balancing airflow reduce energy waste and improve comfort.
Thermostat Settings and Scheduling
Setting the fan to Auto instead of On reduces continuous blower operation, cutting standby energy. Smart or programmable thermostats can optimize heat calls and circulation, lowering monthly consumption without sacrificing warmth.
Maintenance and System Condition
Dirty filters, clogged coils, or a failing inducer fan can force the system to work harder, increasing electricity draw and gas usage. Regular maintenance keeps the system operating efficiently.
Ways To Reduce Electricity Use
Homeowners can trim monthly electricity costs from a gas furnace with several practical steps, often with a favorable payback period if a retrofit is required.
if your furnace has an older PSC motor and you plan to stay in the home long-term. ECMs deliver energy savings and improved comfort, especially in drafty houses. Use a programmable or smart thermostat to minimize heat calls and set the fan to Auto to avoid unnecessary blower operation. Repair leaks and insulate accessible ducts to improve airflow and reduce blower workload. Weatherize doors, windows, and attic spaces to reduce heating demand and the period during which the furnace must run. Change filters, clean or service the burner and inducer, and ensure proper venting to keep the system running efficiently. If feasible, zone heating or staged operation reduces overall energy consumption by heating only areas in use. Electricity costs vary by region. Use your local rate to calculate monthly costs and track changes over time.
Quick Reference: Power Draw By Component
| Component | Typical Wattage (W) | Notes |
|---|---|---|
| Blower Motor (PSC) | 250–500 | Higher idle draw; varies by size |
| Blower Motor (ECM) | 100–300 | Variable, more efficient; depends on speed |
| Induced-Draft/Exhaust Fan | 60–150 | Runs during heat operation |
| Electronic Ignition & Control Board | 5–20 | Primarily during operation; small standby draw |
| Standby/Controls | 1–5 | Continuous additional load |
| Condensate Pump | 4–20 | Active only when connected and used |