What is an LED?
The Bottom Line
This article describes a scenario where Ohms and Watts Services (OWS) were called upon to replace traditional fluorescent lamps in a large school sports hall. This real-life example illustrates the benefits of re-fitting, with relevant facts and figures.
The sports hall has overhead nets installed - to allow the space to be used for indoor cricket practice, for example. Furthermore, the ceiling is very high. Therefore, changing fittings involves dismantling the nets to gain access, followed by use of a "cherry picker" crane to lift the maintenance personnel to the dizzy heights of the tube holders. The less this rigmarole is undertaken, the better, and hence there is an ancillary saving associated with use of the new LEDs.
And another thing: where does all that extra energy used by the old types of fluorescent bulbs go? Well, to a large extent it is dissipated as heat. It's fine to have heat when you want it, but not at the peak of summer, and probably not in the roof space.
Speaking of environmental benefits, there is also the disposal of the fittings, once exhausted, to think about. Standard tubes contain mercury, a notorious pollutant. This imposes a further management burden: the need for them to be properly dealt with at a designated recycling centre.
And another thing ... what about the quality of the light itself? Although the flicker of traditional tubes has been improved over the years, there may still be that almost-imperceptible wobble in the light quality. This may prove irritating in a sports hall, or a location such as a library where sustained visual focus is a necessity. LEDs also do not suffer from faint buzzing sounds and similar anomalies.
Governments in other parts of the world are introducing similar regulations. If the trend continues, it seems likely that smaller organisations will become corralled into the regulations, as time goes on.
This puts an additional pressure on companies, public services and government bodies to adopt carbon-friendly technologies, such as LED tubes. Even if your organisation does not currently fall under the remit of the major legislation, similar rules may apply later. It may also be said that decisions will increasingly be driven by an implicit reputation-based pressure, deriving from the changing culture: organisations will want to deal with partners who are "seen to be green".
Additional beneficial features of LEDs include robustness (including being able to operate at low temperatures, and being relatively unaffacted by sources of interference such as magnetism), smaller size and faster switching speed.
Electricity prices are usually quoted in terms of "kilowatt hours" (kWh). A kilowatt is a unit which measures power usage per unit time. The price per kWh for domestic use (as of the end of 2001) is around 12 pence. Information about current prices in the United Kingdom can be obtained from OFGEM (www.ofgem.gov.uk), the government organisation which regulates prices. Prices for businesses varies widely, depending on credit worthiness, amount of consumption, location and trade sector.
Let's assume a price of 10 pence per kWh for this example. The sports hall had about 200 standard tubes, consuming 70W each. High walls without low windows in the facility mean that natural light is not abundant, so the lights are used even in summer. As a conservative estimate, let's assume that the hall is used on around 275 days a year (note that it is used for events even out of term time, and at weekends for various functions). Further, an estimate of an average 6 hours' use per day is allowed for.
Maintenance used to be done once a year (the lifetime of a standard bulb), and would involve the hire of a cherry picker and electrician for a number of days. The cost of this was £1500. Now, this cost can be spread across ten years.
One thing that skews the calculation against LED tubes is the fact that they are still more expensive than standard tubes. At the time of the installation (in 2011), a standard bulb retailed at about £6, whereas an LED replacement tube was £50. OWS offers competitive industry prices, but there remains, nevertheless, a significant difference in price.
|1||TOTAL POWER USAGE:||200 x 70W = 14000W (or 14kW)|
|2||COST PER HOUR:||14 x 0.1 (i.e. 10p per kWh) = £1.40|
|3||COST PER DAY:||£1.4 X 6 = £8.40|
|4||COST PER YEAR:||£8.4 X 275 = £2,310.00|
|5||MAINTENANCE COSTS (per year):||£1500|
|6||TOTAL POWER USAGE:||200 x 28W = 5600W (or 5.6kW)|
|7||COST PER HOUR:||5.6 x 0.1 (i.e. 10p per kWh) = £0.56|
|8||COST PER DAY:||£0.56 X 6 = £3.36|
|9||COST PER YEAR:||£3.36 X 275 = £924.00|
|10||MAINTENANCE COSTS (per year):||£150|
|11||LED BULBS ADDITIONAL COST (per year):||((200 x £50) - (200 x £6)) / 10 = £880.00|
|12||ORIGINAL TOTAL (per year):||£2,310 + £1,500 = £3,810.00|
|13||LED TOTAL (per year):||£924 + £1,500 = £1,074.00|
TOTAL SAVING (per year):
£3,810 - £1,074 - £880 = £1,856.00
If you would like more information about our energy-saving LED services, please contact us.