The National Trust sees the eco light

Tag : fluorescent whitening



For its historic rooms the Trust has chosen a low-energy halogenbulb instead of the widely available compact fluorescent light bulb(CFL). Low-energy halogen bulbs give out light that is sparkly,closer to daylight and whiter than incandescent light.
The Trust's light bulb moment came when it persuaded themanufacturer Philips to customise the bulb to make sure that itemitted less ultraviolet (UV) light than either incandescent or CFLbulbs. For a little known further sin of CFLs is that some emitmore ultraviolet light than the traditional incandescent perfectedby Thomas Edison in 1879.
As Katy Lithgow, the Trust's head conservator, explains: "UVradiation, beyond the blue end of the visible light spectrum, isthe most damaging component of light and can very quickly fade thelight-sensitive dyes and organic materials in textiles, tapestries,leather and watercolours. It destroys the chemical bonds, which alllight does but UV does more rapidly."
Sparkly light, says Lithgow, is what you need where rooms used tobe lit by gas lamps or candlelight and where lighting was enhancedby being reflected in mirrors. An incandescent bulb is, of course,quite different to candlelight, so does it really matter?
"It's about managing the change, so you have a quality of lightthat is pleasing if not exactly the same," she says. Daylight isthe Trust's first choice, she says, because that is the mostenergy-saving of all.
The Master Classic, the Trust's bulb of choice for historicinteriors, comes in two strengths: 20 watts, which is equivalent toa 40 watt incandescent bulb, and 30 watts, which is equivalent to a60 watt conventional bulb. Both can be dimmed. This helps, as theequivalent of a conventional 25 watt bulb does not yet exist.
Sharp eyes will spot that the Master Classic, Philips's low-energyhalogen bulb, saves only 50 per cent of the energy emitted by astandard incandescent bulb. That compares with 80 per cent savingsfor CFLs and 95 per cent for light emitting diodes (LEDs), the hopeof the future (at the moment LEDs are too weak).
So the Trust is fitting CFLs where the quality of the light is notcritical: in service corridors, in canteens, bedrooms and offices.It has found plug-in energy-saving alternatives for most bulbs,even older fluorescent strips. It is providing advice to itsproperty managers via a website run by a Bristol-based company,Lighting Services.
This starts with the existing fitting and shows the carbon-savingalternative and cost saving. The energy-saving halogen bulbs areavailable at John Lewis, Homebase and Robert Dyas, where they arecalled Eco Classic, and cost between £1.99 and £6.95.
The Trust has found no alternatives for some things, such as the 35watt halogen lamps ubiquitous in picture galleries and modernkitchens. The Master Classic bulbs are too heavy for some elderlychandeliers and light fittings, so incandescent bulbs will still beused there.
One advantage of energy-saving bulbs is that they last thousands ofhours longer than conventional bulbs, which cuts down onmaintenance costs while saving money.
"There may well be better energy-saving bulbs only just around thecorner," says Lithgow, "but the cash and carbon savings presentlyavailable make delay hard to justify."
Don't expect energy-saving bulbs to stop being controversial,though. Last week, rumours swept through the Trust that its newhalogens were exploding upon installation. According to a Trustspokeswoman, an investigation concluded that the story was untrue -one dud bulb was found.
The National Trust's Big Switch Number of properties: nearly 500 Number of bulbs to change: 40,000 Potential savings: £431,000 in electricity and maintenancecosts (because low energy bulbs last longer) Cost of the Big Switch: £189,853. Carbon savings: 2,223 tons of carbon Equivalent to: boiling 136,000 cups of tea Annual savings of fitting one Master Classic bulb: £41.92 Annual savings of one CFL bulb: £74.69 Number of mercury containing bulbs that can be recycled each yearby Mercury Recycling, at Trafford Park, Manchester: 40 million.