The useful answerApartment baseload electricity is the recurring background use that remains during quiet periods. It can include both continuous electronics and cycling appliances. A single low or high interval is not enough to identify every always-on device or predict a full month.

Choose a quiet comparison window

Look for several periods when cooking, laundry and optional entertainment are inactive. Record whether heating, cooling, water heating or refrigeration still operates. An unoccupied apartment is not an electrically inactive apartment.

Utility interval downloads can help locate repeated patterns. PG&E’s customer tools are one example; check your own provider’s data units and availability. Use comparable windows rather than the lowest isolated point on the chart.

Calculate an average over the window

Suppose a six-hour overnight period uses 0.90 kWh. Average power is 0.90 ÷ 6 = 0.15 kW, or 150 W. If that average persisted for a full 30-day month, it would use 108 kWh and cost $19.44 at $0.18/kWh.

That monthly result is a projection, not proof of a constant 150 W load. A refrigerator or heater may cycle, and daytime conditions can change its use. Compare several nights before choosing a working estimate.

Compare several nights without choosing only the lowest

Hypothetical quiet periods, not apartment benchmarks
ObservationEnergy / durationAverage power
Night A0.90 kWh / 6 h150 W
Night B1.20 kWh / 6 h200 W
Night C0.96 kWh / 8 h120 W
All three3.06 kWh / 20 h153 W

The pooled average is 3.06 ÷ 20 × 1,000 = 153 W. It uses the actual duration of each period. Averaging the three watt values without weighting the longer night would answer a different question. Record temperature and equipment settings beside each observation.

Extending 153 W through every hour of a 30-day month gives 110.16 kWh, or about $19.83 at $0.18/kWh. That is a sensitivity scenario. Overnight conditions may not represent daytime use, so do not call it a measured monthly baseload or a guaranteed saving available to remove.

Build a short device inventory

List refrigeration, networking, clocks, standby electronics and any required building or safety equipment. Add credible measured or documented energy estimates where available. Do not assume the entire unexplained remainder is waste.

Use normal controls only for optional devices that can be safely switched off, one change at a time. Do not disable essential medical, safety, food-storage or required ventilation equipment to force the meter toward zero.

Investigate a material unexplained change

Compare a new pattern with your own previous baseline, noting weather, guests and new equipment. A persistent step change may justify checking settings or requesting maintenance. If meter assignment is a concern, ask the provider or property manager to investigate; do not open panels or alter wiring. The useful deliverable is a dated set of observations and plausible questions, not an accusation based on one overnight graph.

Decide whether another observation is needed

If a repeated overnight increase coincides with a known heating or cooling change, investigate that schedule first. If the export contains missing or estimated readings, resolve those using the interval-data checks before explaining the pattern.

There is no universal watt target in this guide. A household with essential powered equipment cannot be judged against a smaller equipment inventory. Record the specific unexplained difference and its dates; do not disconnect necessary systems to make a graph flatter.

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.