LED vs Incandescent Savings

LED vs incandescent savings

For the same amount of light, an LED draws about 10× less power than an incandescent bulb. A 60 W incandescent putting out ~800 lumens matches a 9 W LED at the same brightness. To find the yearly energy per lamp, use kWh/year = W · hours_per_day · 365 / 1000. Say you run it 4 h/day: the incandescent burns 60 · 4 · 365 / 1000 = 87.6 kWh/year, while the LED uses only 9 · 4 · 365 / 1000 = 13.1 kWh/year. That's 74.5 kWh saved per lamp per year, roughly BRL 60 at R$ 0.80/kWh. Now multiply across every fixture: swap out 10 bulbs and you're looking at ~745 kWh/year. In Brazil the labels are regulated by Inmetro (PBE Edifica program), so LED lamps have to state lumens, watts and color temperature (warm 2700-3000 K, neutral 4000 K, cool 6500 K). They also last a long time — 15,000-50,000 hours, versus the 1,000 hours you get from an incandescent.

Applications

Home retrofits give the best return, but the same math applies to commercial buildings, public street lighting (the Curitiba and São Paulo concessions), high-bay swaps on factory floors, and the energy audits that feed ESG reports.

FAQ

What's the payback for replacing one bulb? Run an incandescent 4 h/day and a BRL 8 LED pays for itself in under 2 months on energy alone. That's before you factor in all the burnt-out bulbs you won't have to buy.

Are LEDs really equivalent in brightness? They are, but you have to read lumens rather than watts. 800 lm covers a 60 W incandescent, and 1,100 lm matches a 75 W. Keep an eye on color rendering (CRI ≥ 80) and color temperature too.

Do LEDs save on heat too? They do. An incandescent throws off about 90% of its energy as heat, so going LED takes load off the air conditioner in summer. In a tropical climate that stacks on top of the lighting savings.