In this guide
Define the numerator and denominator first
An occupied room-night is one room occupied for one night. Two guests sharing that room still represent one occupied room-night. A 100-room hotel at 80% occupancy over 30 days would have 2,400 occupied room-nights if that simplified room inventory and occupancy basis applies throughout.
Use the actual occupancy-system total when available. Document treatment of complimentary rooms, staff use, out-of-service rooms and reporting adjustments. The rule should be visible and consistent rather than hidden in a spreadsheet formula.
For energy, list each included stream and its original unit. Electricity may already be in kWh. Gas, fuels or purchased heat may require documented conversions. Keep electricity-only analysis separate when the other streams are incomplete.
A fictional two-period example
| Measure | Period A | Period B |
|---|---|---|
| Electricity consumption | 120,000 kWh | 132,000 kWh |
| Occupied room-nights | 2,000 | 2,400 |
| Electricity intensity | 60.00 kWh per occupied room-night | 55.00 kWh per occupied room-night |
Electricity use rose by 10%, while electricity intensity fell by about 8.3%. Both statements are true. The ratio improved partly because more occupied room-nights shared the building's electricity use. This example does not establish an energy-saving intervention or a reduction in absolute consumption.
Try the calculation
The starting numbers are fictional. Use matching periods, units and boundaries.
A simple arithmetic check. It does not validate your source records or method.
Report the total alongside the ratio. If the hotel had no occupied room-nights, leave the ratio unavailable and explain the closure or missing data. Dividing by zero or replacing the result with zero would mislead the reader.
Match bills and occupancy dates
A utility bill running from 18 March to 17 April will not match an April occupancy report. Use interval-meter data where suitable, or apply a documented allocation approach when needed. Retain the original bill, the allocation method and the resulting period total.
Check estimated readings, subsequent bill corrections and multiple meters. Confirm whether the hotel pays for a neighbouring tenancy or excludes a leased restaurant. A change in those arrangements can move the metric without any change in equipment performance.
The worksheet keeps energy evidence and occupancy evidence in separate fields because the numerator and denominator can fail independently. An accurate electricity invoice does not validate the room-night total.
Compare like with like
Start with the same property on a consistent basis. Record changes in weather, operating days, floor area, facilities and service level before comparing periods. For comparisons between hotels, investigate differences in climate, food service, laundry, meeting space and other activities.
An area-based metric can answer a different question. ENERGY STAR describes energy use intensity as energy relative to building size or other characteristics. Keep the area definition and energy basis explicit; a ratio per square metre is not interchangeable with a ratio per occupied room-night.
Avoid labelling one universal kWh-per-room figure as a target for every property. A published portfolio average describes its own sample and boundary, which may differ materially from yours.
Energy and carbon are different measures
Multiplying energy by an applicable emissions factor can form part of a carbon calculation, but an energy ratio itself is not a carbon footprint. The Hotel Carbon Measurement Initiative provides a hospitality-specific methodology and free tool for carbon measurement, including a per-occupied-room measure. Use its actual methodology when making an HCMI-based claim; this worksheet is not an HCMI calculator or certification.
If a prepared climate figure will be disclosed, retain the source records, calculation and review decision. The guide to reproducing emissions figures covers that evidence trail.
Questions to resolve before publishing the number
Can electricity alone be useful?
Yes, if it is labelled electricity intensity and the comparison uses the same scope. Do not silently add gas in one period while retaining an electricity-only label in the other.
Does lower intensity prove better efficiency?
It can be a useful signal, but occupancy and other operating changes also affect the denominator and energy demand. Investigate the drivers before attributing a reduction to an intervention.
What should the reviewer retain?
The bill or meter export, occupancy report, boundary note, conversion or allocation workings, calculation version and explanation of corrections. Those records let someone else reproduce the published result.
Prepared with AI assistance using the linked sources and original fictional examples. No customer results, field measurements or independent specialist review are claimed.