Our office currently runs standard fluorescent strip lights (1500mm T8 tubes) throughout, with over 60 bulbs across 3 floors. We are considering upgrading all the lights to LED bulbs, in order to save power and to make them compatible with an office automation system (to turn them on and off automatically).
So, how much energy will they save? Well a standard fluorescent bulb consumes about 58w, whereas the new LED bulbs consume around 20W. Therefore over the course of a year I would anticipate the energy savings to be as follows:
|Standard Fluorescent Bulb||LED Bulb|
|Power Consumption||58 Watts||20 Watts|
|Hours in use||10 hours per day, 5 days a week, 52 per year|
|Hours per year||2,600|
|Kilowatt hours per year (watts / 1000 * hours)||150.80 kWh||52 kWh|
|Cost per year (at 10p per kWh)||£15.08||£5.20|
Thus the saving is about £10 per year per bulb.
We are currently asking suppliers to quote us for 60 bulbs, and the prices we have received so far range between £25 to £60 per bulb.
The bulbs are rated for about 50,000 hours of constant usage, which should mean they would last nearly 20 years at the rate of usage we have forecast.
Standard bulbs last about 5,000 hours (2 years) and cost around £2 each.
It looks like the energy saving bulbs should pay for themselves after 3 – 5 years, and return a yield of around 20% thereafter.
Things I haven’t factored in:
- Cost of installation / replacing bulbs (slighty more difficult to initially install, but they last 10 times as long and therefore need less labour to replace).
- Reduced heat from operation – might require less air conditioning in summer months)