Define the gaming setup
List the tower, display, speakers and other powered equipment included in your estimate. A wall measurement of the whole desk already includes those connected devices; a graphics-card power figure does not. Keep software telemetry separate from complete wall-socket energy.
Record the game or workload, settings and session length. Different workloads on the same hardware can produce different input, so a brief peak during a demanding scene is not a reliable average for every evening.
Calculate a session-based month
Assume the tower averages a hypothetical 400 W while gaming for three hours on each of 30 days. That is 0.4 × 3 × 30 = 36 kWh, costing $6.48 at $0.18/kWh.
A separate 30 W monitor on the same schedule adds 2.7 kWh and about $0.49. The combined illustrative gaming cost is about $6.97. Idle desktop time, sleep and any other accessories remain outside those figures.
Add the hours between games
If the tower stays on while you are away, record its actual idle state and duration. A running game, download or background job may prevent the low-power behavior you expected. Check the operating system’s settings and confirm the machine enters the intended state.
ENERGY STAR distinguishes active, idle and lower-power operation. Use separate rows for those periods instead of applying gaming watts across all 24 hours.
Test one reversible change
Compare an appropriate frame-rate limit or idle timeout using the same workload and an acceptable gaming experience. Record both performance and energy, without assuming a universal saving from a single setting. Do not confuse a lower-power component with a guaranteed lower whole-system bill. If the current PC still meets your needs, compare any replacement premium with plausible annual savings before framing an upgrade as a way to save electricity.
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.