Energy Conservation, Efficiency and Consumer Awareness
What the exam tests
This domain tests efficiency, energy consumption, BEE star ratings, load management, standby loss, maintenance and consumer rights and markings.
Core rules
- Efficiency is useful output divided by input, expressed as a percentage. Losses appear as heat, sound or standby power.
- Energy in kWh = power in kW × time in hours. The tariff applies to kWh, not to watts alone.
- BEE star labels compare similar appliances; more stars mean lower energy use for the same service. Star rating is not a measure of capacity or build quality.
- Conservation measures include LED lighting, five-star appliances, switching off standby loads, correct sizing, clean filters, lagging hot-water pipes and regular maintenance.
- Consumers should check ISI/BIS marking where applicable, warranty, authorised service and a proper bill; keep the manual and complaint record.
Worked example
A 100 W incandescent lamp is replaced by a 9 W LED used 5 hours a day. Saving = (0.100 − 0.009) kW × 5 h × 365 = 166 kWh per year. At ₹8 per kWh the saving is about ₹1,328 per year. The LED also reduces cooling load in summer.
Traps
Do not confuse star rating with wattage. Do not call a power factor correction device an efficiency improvement without checking losses. Do not ignore standby power. Do not buy an unbranded appliance without safety marking to save a small amount.