💡 Lighting Efficiency
Lighting Energy Calculator
Calculate energy consumption, cost, and savings for lighting systems.
Bulb Type
Number of Bulbs
bulbs
Total number of bulbs in use
Wattage per Bulb
W
Power consumption per bulb
Daily Usage Hours
hrs
Average hours per day the lights are on
Days per Year
days
How many days per year the lights are used
Electricity Rate
$
/kWh
Cost per kilowatt-hour
Energy
0%
Annual Cost
$0.00
yearly lighting cost
Energy Used
0 kWh
Monthly Cost
$0.00
Total Wattage
0 W
Bulbs
0
📐 Lighting Formulas
Energy = W × hrs × days ÷ 1000
kWh per year
Cost = Energy × Rate
Annual Cost
Total W = Bulbs × Wattage
Total Power
Savings = Cost_old − Cost_new
Upgrade Savings
📊 Lighting Breakdown
| Metric | Value | Description |
|---|
How the formula works
Energy (kWh) = (Wattage × Hours × Days) ÷ 1000 | Cost = Energy × Rate
- Energy = (Total Wattage × Daily Hours × Days per Year) ÷ 1000 (kWh)
- Total Wattage = Number of Bulbs × Wattage per Bulb
- Annual Cost = Energy × Electricity Rate
- Monthly Cost = Annual Cost ÷ 12
- Bulb Types: Incandescent (60W), CFL (14W), LED (10W), Halogen (43W) typical