Home Office Energy Calculator
Working from home shifts some of your employer's electricity bill onto yours — but the direct equipment cost is usually smaller than people expect. This calculator adds up the wattage of your computer, monitors, and peripherals, multiplies by the hours and days you actually work, and applies your electricity price to estimate the annual cost. It covers equipment electricity only — not the larger cost of heating, cooling, and lighting the space itself, which you can estimate with our HVAC Energy Cost Calculator, or the savings from switching to efficient lighting with our LED Lighting Savings Calculator.
Selecting a type auto-fills the computer wattage below (still editable).
A typical desktop tower draws around 150 W; a laptop around 50 W under normal use.
Each monitor is assumed at roughly 30 W.
Average hours your office equipment is powered on per working day.
Number of days per week you typically work from home.
Combined wattage of peripherals running alongside the computer and monitors.
The U.S. average residential rate is about $0.17/kWh; adjust to your local utility rate.
computer wattage + (number of monitors × 30 W) + other equipment power
(total equipment power × hours used per day) ÷ 1,000
daily energy use × working days per week × 52
annual energy use × electricity price
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →A typical home office setup -- desktop computer, two monitors, and miscellaneous equipment running 8 hours a day, 5 days a week -- costs under $85 a year in direct electricity at average U.S. rates. Switching from a desktop to a laptop alone can cut that by roughly 40%, since laptops typically draw a third of the power of a comparable desktop setup. The bigger home-office energy cost usually isn't the equipment itself -- it's the heating, cooling, and lighting for the space, which this calculator doesn't include.
How home office energy use is calculated
This calculator ties the annual electricity cost of a home office to six inputs: computer wattage, monitor count, hours used per day, working days per week, other equipment power, and your electricity price. Four quantities tie the calculation together.
Total Equipment Power (W) = Computer Wattage (W) + (Number of Monitors × 30 W) + Other Equipment Power (W). Each monitor is assumed to draw roughly 30 W, a typical figure for a modern LCD/LED display; at a 150 W desktop, 2 monitors, and 30 W of peripherals, that is 150 + (2 × 30) + 30 = 240 W.
Daily Energy Use (kWh) = (Total Equipment Power (W) × Hours Used per Day) ÷ 1,000. Watts × hours gives watt-hours; dividing by 1,000 converts to kilowatt-hours, the unit your utility bills. At 240 W and 8 hours, that is (240 × 8) ÷ 1,000 = 1.92 kWh/day.
Annual Energy Use (kWh) = Daily Energy Use (kWh) × Working Days per Week × 52. This scales the daily figure up to a full year of working weeks; at 1.92 kWh/day and 5 working days, that is 1.92 × 5 × 52 = 499.2 kWh/year.
Annual Cost ($/year) = Annual Energy Use (kWh) × Electricity Price ($/kWh). At 499.2 kWh and $0.17/kWh, that is 499.2 × 0.17 = $84.86/year.
Two notes on the model. First, the calculator covers equipment electricity only — it does not include the typically larger cost of heating, cooling, and lighting the home office space itself, which a space heater, window AC, or dedicated lighting can easily exceed. Second, monitor wattage varies with size, resolution, and brightness, and computer wattage varies with workload (a desktop gaming or rendering under load draws far more than when idle), so treat the 30 W/monitor and 150 W desktop figures as planning averages and adjust to your actual equipment. Data sources: desktop and laptop power consumption from equipment manufacturer specifications and energy efficiency studies; monitor wattage from typical LCD/LED display power ratings; home office equipment power draw from DOE and EPA energy guides; average U.S. residential electricity rates from EIA data.