Choose the system boundary first
A plug-in Wi-Fi camera may have its own adapter, while a wired camera can receive power from a network switch or recorder. Decide whether you are calculating one camera, all camera ports, or the complete security system. The result is misleading if the recorder is omitted in one option but included in another.
Battery cameras need a different boundary. Their wall energy appears during recharging or at a base station rather than as constant camera input. Measure the charger session and frequency rather than assigning a continuous plug wattage to the camera.
Calculate a continuous-load scenario
For a camera averaging 5 W, energy is 0.005 kW × 24 hours × 30 days = 3.6 kWh. At $0.18/kWh, the cost is $0.648, or about $0.65. Four identical cameras at the same average use 14.4 kWh and cost $2.59.
Night illumination, live viewing, recording, wireless activity and temperature can change actual draw. Use cumulative energy across day and night when possible, not only the adapter’s maximum output rating.
| Number of 5 W cameras | 30-day energy | Cost at $0.18/kWh |
|---|---|---|
| 1 | 3.6 kWh | $0.65 |
| 4 | 14.4 kWh | $2.59 |
| 8 | 28.8 kWh | $5.18 |
If the camera adapter is difficult to meter, measure the complete shared supply over a representative day and divide only when the cameras and settings are genuinely equivalent. Keep any base-station or recorder load outside that division so it is not counted repeatedly.
Add the shared equipment once
If four cameras share one 12 W recorder and one 8 W switch, add those shared loads once, not four times. At a constant combined 20 W, shared equipment uses another 14.4 kWh and costs $2.59 over 30 days at the example rate.
A router already required for the household may be treated as an existing baseline, while a dedicated switch is incremental. State the choice rather than hiding it. Cost allocation and physical energy use are related but different questions.
Do not let energy estimates replace security planning
Electricity cost does not establish image quality, privacy, cybersecurity, data retention or legal suitability. Follow manufacturer update and account-security guidance and applicable rules for camera placement and recording.
For an auditable energy log, list each powered component, measured average or period kWh, operating hours and rate. Recheck after enabling continuous recording, adding night lighting or changing storage because those choices can move the system outside the original estimate.
Choose your next step
Continue with the question that matches your next decision:
Sources & further reading
Numerical examples are illustrative unless explicitly described as measured. This guide does not claim hands-on product testing. Read the methodology and editorial disclosure.