A measured row uses a plug-in meter on one device that already has a plug you use. Keep the observed device mode. An average-watts display is not the same as an instantaneous observation. An assumed watt stays in its own column. Any annual kilowatt-hour figure is a scenario, including when the wattage was measured and the hours were assumed. This sheet is for individual devices. There is no site total.

Keep the visual equipment check separate from a watt reading. Do not enter a scenario into the bill as if it were billed consumption. Read the green claims guide before calling a scenario a measured saving.

Measured watts and assumed watts

measured_power_w is filled only for measurement_method plug_meter. assumed_power_w is never copied into that cell. A nameplate, a remembered figure and a legal limit are assumptions.

Safe plug use follows the instrument or manufacturer limit written on the meter you hold. Do not treat a foreign laboratory wattage as a UK plug rule.

Generator standby is a different product. Fixed wiring, heaters, ventilation, anything your meter is not rated to measure, and any device you do not already unplug in ordinary use stay not_measured.

Fill in the worksheet

Download both files. Save a copy of the blank sheet and type into that copy.

The files are plain CSV. You type every cell. You do the conversion. The spreadsheet does not calculate a row and it does not reject a typed value.

The same blank fields are:

device_label, socket_label, mode_observed, measurement_method, measurement_display, measured_power_w, measured_wh, duration_minutes, assumed_power_w, scenario_hours, annual_period_start, annual_period_end, annual_kwh_scenario, annual_label, instrument_limit_note and row_status.

mode_observed is off_at_switch, standby_display_on or other_described. Keep it on every row. measurement_display is average_watts, instantaneous_watts or watt_hours_interval.

Watt-hours convert only when duration_minutes is a positive finite interval: watt-hours times 60, divided by minutes. A blank, zero, negative or non-finite interval leaves the conversion blank. If both a direct watt and a convertible interval are present, they must agree within 0.05 W or the row is inconsistent_inputs.

scenario_hours must be a non-negative finite number. annual_period_start and annual_period_end are required before an annual figure can be written, and the end date must be on or after the start date. The maximum hours for that scenario are 24 times the inclusive calendar days of those dates. 1 January to 31 December 2026 is 365 days and 8760 hours. A shorter period cannot use a full-year allowance. A leap-year 1 January to 31 December is 366 days and 8784 hours. Missing or reversed dates cannot establish an annual result. Hours above that period’s own maximum, or any negative hour count, cannot yield a valid scenario. Zero hours or zero power can yield 0.00. Whenever an annual figure is present, annual_label is scenario_not_measured_year.

Do not sum rows.

What stays unmeasured

Leave plant, heaters and electrical spaces closed. Those rows have blank power cells and row_status not_measured.

Worked example: a fictional monitor

Northgate Studio is fictional.

Device What was written Status
Reception monitor Plug meter. Mode standby display on. 0.25 watt-hours over 10 minutes. 0.25 × 60 ÷ 10 = 1.50 W. 1.50 × 2000 ÷ 1000 = 3.00 scenario kilowatt-hours for 1 January to 31 December 2026, which allows at most 8760 hours. Measured watts. Annual figure labelled scenario_not_measured_year.
Office printer No meter. Assumed 4 W. Same 2000 hours. 8.00 scenario kilowatt-hours. Measured watts blank. Assumption. Not added to 3.00.
Wall heater Not measured. Both power cells blank. not_measured.

Limits

The annual figure is a scenario. It is not the bill and not a year of metered consumption. Before you describe the scenario as waste that was removed, read the green claims guide.

Sources