Use the fields below to compare yearly energy use, running costs, replacement needs, carbon impact, and total ownership cost.
Energy (kWh) = [Number of bulbs × Wattage × Hours used] ÷ 1000
Running cost = Energy (kWh) × Electricity rate per kWh
Annual savings = Annual halogen cost − Annual LED cost
Replacements per bulb = Ceiling(Analysis hours ÷ Lifespan hours) − 1
Ownership cost = Initial bulb cost + Replacement cost + Operating cost over the selected years
Payback months = Extra LED upfront cost ÷ Monthly running cost savings
| Bulbs | LED W | Halogen W | Hours/Day | Rate/kWh | LED Annual kWh | Halogen Annual kWh | Annual Savings |
|---|---|---|---|---|---|---|---|
| 12 | 7 | 50 | 5 | $0.18 | 153.30 | 1095.00 | $169.51 |
| 8 | 9 | 42 | 4 | $0.20 | 105.12 | 490.56 | $77.09 |
| 20 | 10 | 60 | 6 | $0.15 | 438.00 | 2628.00 | $328.50 |
Example values assume comparable brightness levels and steady daily usage patterns.
1) Why do LEDs usually save more energy than halogen bulbs?
LEDs convert more electrical power into light and less into heat. That means they usually need far fewer watts for similar brightness, so yearly electricity use and utility bills drop noticeably.
2) Does lower wattage always mean lower brightness?
Not always. Wattage measures power draw, not brightness. For a fair comparison, match the bulbs by lumens or expected light output, then compare energy use and cost.
3) Can I use this calculator for homes, offices, and shops?
Yes. The calculator works for almost any lighting setup. Enter the bulb count, usage hours, electricity tariff, and bulb costs that match your real space.
4) What electricity rate should I enter?
Use the rate you actually pay per kilowatt-hour on your utility bill. If your tariff changes by season or time, enter an average rate for a balanced estimate.
5) Why does lifespan matter in the comparison?
Lifespan affects how often you replace bulbs. Even if LEDs cost more upfront, fewer replacements can reduce total ownership cost over several years.
6) What does payback period mean here?
Payback shows how long it takes for monthly electricity savings to recover any extra upfront cost of choosing LEDs instead of halogen bulbs.
7) Can this calculator estimate environmental impact too?
Yes. Enter a CO₂ factor for your electricity source. The calculator then estimates annual and multi-year carbon savings from switching to LEDs.
8) Should I compare bulbs with equal wattage?
No. Compare bulbs that deliver similar brightness. Equal wattage bulbs may produce very different light output, which can distort the real savings picture.