kWh in one paragraph
A kilowatt-hour (kWh) is one kilowatt of power used for one hour. It is the 'unit' on your electricity bill. A compressor drawing 250 W that runs for 12 hours in a day uses 3 kWh. That is why the wattage on the rating plate is not enough: the daily kWh depends on how many hours the compressor runs, which depends on insulation, door openings, room temperature and how well the unit is built.
kWh per 24 h versus kWh per year
BEE labels for appliances such as chest deep freezers show annual energy consumption. BEE's method takes the measured 24-hour consumption and multiplies it by 365. So a label that reads 730 kWh per year corresponds to 2 kWh per 24 hours under test conditions. To convert a spec-sheet figure the other way, multiply kWh per 24 h by 365.
| kWh per 24 h | kWh per year (×365) | Units per month (approx.) |
|---|---|---|
| 1.5 | 548 | 45 |
| 3.0 | 1,095 | 90 |
| 5.0 | 1,825 | 150 |
| 8.0 | 2,920 | 240 |
The test conditions are half the number
A kWh figure is only meaningful alongside the conditions it was measured in. Look for the room temperature and humidity, the cabinet temperature being held, whether doors were opened during the test, and whether lights and anti-fog heaters were on. For retail display cabinets, ISO 23953 tests are commonly run in climate class 3, which is 25 °C and 60% relative humidity. Indian shop floors and kitchens are often much hotter.
Two figures measured under different conditions cannot be compared directly. A cooler tested at 25 °C will always look better than one tested at 32 °C, even if the second is the better machine.
What labels and spec sheets leave out
- Your ambient: a 40 °C kitchen can raise consumption well above the test figure.
- Your door openings: busy service means more warm air in and more run time.
- Hot loading: putting in warm stock or cooked food adds heat the test did not include.
- Maintenance: a dusty condenser or tired door gasket quietly raises consumption month after month.
- Voltage: low supply voltage makes compressors draw more current and run hotter.
How to compare two units fairly
Ask both suppliers for kWh per 24 h measured to a named standard and at a stated ambient. Compare units of similar internal volume and the same temperature band. If one is bigger, divide the daily kWh by the storage volume to get kWh per litre per day, which levels the field a little. Finally convert to rupees with your tariff and look at the difference over the years you expect to own the unit.
Checking real consumption on site
A plug-in energy meter, or a sub-meter on the circuit, will show what the unit uses in your conditions. Measure over at least a full week so busy and quiet days are included, then divide by the number of days. If the result is far above the label or spec figure, look at ambient temperature, condenser cleanliness, door seals and loading habits before blaming the machine.
Frequently asked questions
- Do commercial cabinets carry BEE labels like household fridges?
- Some do. BEE labels cover chest deep freezers, and commercial beverage coolers have a voluntary programme. Many other commercial cabinets, such as reach-ins and display counters, have no BEE label, so you rely on the supplier's measured kWh per 24 h and the test conditions behind it.
- Why is my fridge using more than its label figure?
- Labels are measured in a controlled test room. Higher room temperature, frequent door opening, warm stock, a dirty condenser and worn gaskets all raise consumption. Measure over a week and work through those causes one by one.
- Is kWh per 24 h the same as units per day?
- Yes. One unit on an Indian electricity bill is one kWh, so kWh per 24 hours is the number of units the appliance uses in a day under the stated conditions.
Sources
- BEE — Deep freezer notifications and regulations (reference IS 7872)
- ISO 23953-2:2023 — Refrigerated display cabinets: classification, requirements and test conditions
- CLASP policy database — Schedule 37, commercial beverage coolers (India)
