Use meter readings or billed electricity covering a full year. Enter household size, floor area, the previous year’s consumption and old and new unit rates. Keep the boundary consistent: shared heating, EV charging or solar self-consumption can make otherwise similar homes difficult to compare.
Formula
Monthly use = annual kWh ÷ 12. Use per person = annual kWh ÷ occupants; use per m² = annual kWh ÷ area. Annual change = (current − previous) ÷ previous × 100. Tariff impact = annual kWh × (new rate − old rate).
Worked example
A household using 3,600 kWh annually averages 300 kWh per month. With three occupants and 90 m², that is 1,200 kWh per person and 40 kWh per m². These are descriptive ratios, not efficiency ratings.
What the result means
A negative year-on-year change means lower consumption. A positive tariff impact means higher energy spending at unchanged consumption. Check whether occupancy or electric heating changed before attributing a difference to efficiency.
Electricity price · India
Electricity duty, fuel or power purchase adjustments, fixed charges and subsidies depend on the applicable state and DISCOM rules. No national tax percentage or subsidy is assumed. Slab thresholds, sanctioned-load charges and time-of-day tariffs are not automatically modelled.
Assumptions and limits
Average months hide seasonal demand. The calculation excludes standing charges and does not automatically adjust for weather, household changes or billing estimates.
Questions answered
Can I compare partial years?
Use equal, representative periods; a summer-only reading is unsuitable for estimating an electrically heated winter.
Why is the annual percentage unavailable?
A previous consumption of zero does not provide a valid percentage baseline.
Data sources
- Bureau of Energy Efficiency: Star labelled appliances
- BEE: Appliance label and efficiency questions
- Delhi Electricity Regulatory Commission: Consumer bill guidance
- Ministry of New and Renewable Energy: Rooftop solar
Last reviewed: 2026-09-08