The formula
Annual cost (₹) = annual energy (kWh) × effective tariff (₹/kWh). Annual energy is the sum of daily kWh across the year. Because refrigeration uses more energy in hot months, it is better to split the year into seasons than to multiply one day by 365.
Step 1: get a real kWh per day
- Best: measure. A plug-in energy meter rated for the unit's current, left for a full week of normal trading, gives kWh per day under your own conditions. Larger units can be measured with a sub-meter fitted by an electrician.
- Next best: the label or spec sheet. Deep freezers in India can carry a BEE star label with annual energy, and many commercial units list daily energy. These figures come from tests at fixed conditions that may be milder and gentler on door openings than your shop.
- Rough estimate: running watts × fraction of time the compressor runs × 24 h ÷ 1,000. Running fraction rises sharply in hot weather and with heavy door use.
Step 2: work out your effective tariff
Commercial electricity bills in India include energy charges, fixed or demand charges, duties and other components, and the structure differs between states and distribution companies. For a running-cost estimate, take a few recent bills and divide the total amount by the units billed. That effective rate, in ₹ per kWh, is what each extra kWh roughly costs you. Where tariffs have slabs, the marginal rate on your top slab matters more than the average.
Worked example
Assumptions: a two-door reach-in in a restaurant kitchen; measured daily energy of 7 kWh in April to June, 6 kWh in July to September and 5 kWh from October to March; effective tariff of ₹9 per kWh, used here purely as an assumption. Use your own bill.
| Season | Days | kWh/day | kWh | Cost at assumed ₹9/kWh |
|---|---|---|---|---|
| April to June | 91 | 7 | 637 | ₹5,733 |
| July to September | 92 | 6 | 552 | ₹4,968 |
| October to March | 182 | 5 | 910 | ₹8,190 |
| Year | 365 | 2,099 | ₹18,891 |
What pushes the number up or down
- Room temperature around the condenser: the hotter the air, the longer the compressor runs. Moving a unit away from the tandoor or giving it the clearance in its manual is often the cheapest saving available.
- Door openings and loading warm food: both add heat that has to be removed.
- Dirty condenser coils and worn door gaskets: both make the unit work harder for the same result.
- Set point: running colder than the food needs uses more energy. Set it to what your food-safety plan requires, not as low as it will go.
- Night blinds or lids on open display and chest units, where fitted, reduce heat gain while closed.
Using the estimate
Add each unit's annual cost to see the whole site's refrigeration bill. The total helps you decide where improvements pay: a ventilated plant area, a strip curtain on a walk-in, or replacing the worst unit. It also lets you compare units fairly when buying, as long as both kWh figures are measured or rated under the same conditions.
Frequently asked questions
- Can I use the BEE label figure to estimate my bill?
- It is useful for comparing labelled models with each other, because they are tested the same way. Your real consumption will usually differ because your room temperature, door openings and loading differ from the test. Measuring your own unit is more reliable.
- Why is my refrigeration bill higher in summer?
- The compressor rejects heat into hotter air, so it runs longer and uses more power per unit of cooling. Door openings in hot, humid weather also bring in more heat and moisture.
- How do I compare two units of different sizes on running cost?
- Divide each unit's annual cost by its usable capacity, such as shelf positions or usable litres. A larger unit nearly always costs more per year but may cost less per shelf position. Compare on the measure that matches how you use the space.
- Should I include the extra AC load from plug-in units?
- If the units stand in an air-conditioned space, yes. Their net heat into the room is roughly equal to the electricity they use, and the AC must remove it. Dividing that heat by the AC's efficiency gives the extra AC energy, which can be a noticeable addition in a cooled shop.
