40 W Tubelights - Which Brands Last Longer And Burn Brighter
June 30, 2006
INSIGHT - The Consumer Magazine has published the test findings of its in-house comparative product testing laboratory on an extended life test of 5,000 hours on 11 brands of 40 W tubelights in its July-August 2006 issue.
40 W Tubelights
Which Brands Last Longer And Burn Brighter
Normally our policy is to recommend the top three scorers as the Best Buys. In the present case these are : Osram (1st), ECE and GE (both 2nd) and Philips (3rd). But this time we make an exception and include three more brands to the list of Best Buys as their overall scores are only marginally lower than those of the top three. Also, readers’ feedback tell us that often the top three brands may not be available in their particular areas. Hence, to give our readers a wider choice, we also recommend as our Best Buys the 4th highest scorer Anchor Classic with 87, the 5th highest scorer Bajaj with 85, and the 6th highest scorer New Crompton with 84.
We had earlier tested 13 brands of 40 W tubelights as per IS:2418 (Part-1 to 4)-1977 up to a life of 2,000 hours. All samples of 11 out of the 13 brands conformed to the Standards. The two non-conforming brands, which we also found to be fake, were excluded from subsequent life tests.
As per the Standards, to assess the rated life of tubelights, they could be tested up to 70 per cent of their rated or declared life. Though not mentioned on the tubelights or their packing, our correspondence with manufacturers revealed that the rated life is 5,000 hours. Hence, we tested the samples up to 3,500 hours as per the "scope" of IS:2418 part-1-1977 (amendment no. 3). Again, in the interests of consumers, we tested them right up to their rated life, i.e. 5,000 hours, which is not prescribed in the Standards. Brands which work up to 5,000 hours should last two-and-a-half to three years at an average use of five hours a day.
We tested 10 samples each of the 11 brands of tubelights for two IS and five non-IS parameters. The tests were in two parts — the first up to 3,500 hours and the second, up to 5,000 hours.
The two IS parameters were: life test up to 3,500 hours, i.e. how many tubelights continued working up to 3,500 hours; and average lumen maintenance (light output) at 3,500 hours. The light output of a tubelight decreases with its use. It is not enough that the samples continue working, They should also provide adequate light. Lumen (light output) maintenance is a measure of the amount of initial light output maintained by a tubelight during its life.
The five non-IS parameters tested were life test up to 5,000 hours, i.e. how many tubelights continued working up to 5,000 hours, average lumen maintenance at 5,000 hours, average efficacy at 3,500 hours and at 5,000 hours; and the number of tubelights which showed the blackening of the ends. Efficacy is a measure of energy efficiency. It is defined as the light generated in lumens per watt of electrical energy input. The tubelight showing the highest efficacy is one which gives the maximum light and consumes the least amount of power.
Life of the Tubelights
Out of the 11 brands, all 10 tubelights of nine brands worked satisfactorily up to 3,500 hours. One tubelight of Crompton and two of Cema stopped working before 3,500 hours.
The lumen maintenance was checked at certain intervals after 2,000 hours — at 2,800 hours, 3,500 hours, 4,300 hours and 5,000 hours. As per the IS, the average lumen maintenance at 3,500 hours should not be less than 80 per cent of the initial lumen. All the 11 brands conformed to this parameter.
The percentage average lumen maintenance at 3,500 hours was found to be the highest in Osram at 92.78 per cent, followed by ECE at 91.14 per cent and GE at 90.61 per cent. The lowest figure was for Bengal Lamps at 83.28.
We tested all 10 samples of nine brands, nine samples of Crompton and eight of Cema for extended life up to 5,000 hours. All 10 samples of six brands worked satisfactorily up to 5,000 hours with light output more than 80 per cent. These brands were Philips, Osram, GE, ECE, Bajaj and Anchor.
Only five samples of Wipro and Cema and six samples of Bengal Lamps worked up to 5,000 hours.
Average lumen maintenance of only one brand, Bengal Lamps, was found to be less than 80 per cent. Average lumen maintenance of Osram was the highest at 90.27 followed by ECE at 90.16.
The initial ideal efficacy (initial rated lumen divided by initial rated wattage) is 61.25. Efficacy decreases with age and use of a tubelight.
At 3,500 hours, average efficacy of ECE was found to be the highest at 53.43, followed by Philips at 52.80. Bengal Lamps showed the lowest average efficacy of 49.05.
At 5,000 hours, the result was the same with ECE showing efficacy of 52.77, Philips of 51.65 and Bengal Lamps of 45.85.
Blackening of Ends
Black spots were observed on tubelights of Bengal Lamps at the end of 3,500 hours itself. By 5,000 hours all 10 samples of that brand showed blackening. The blackening of the ends indicates that the tubelight’s life may gradually come to an end. None of the 10 samples of Philips, GE and Osram showed the blackening of the ends even after completion of 5,000 hours. All samples of Surya and Cema showed blackening at 5,000 hours.
Philips has claimed on the label and provided an anode ring which prevents the blackening of the ends.
BEE’s Proposed Star Labelling
The Bureau of Energy Efficiency (BEE) has developed an energy labelling programme which will be used to rate tubelight brands. Under the programme, tubelights would be rated on a scale of 1 to 5 stars with the most efficient product carrying a 5-star rating. BEE labelled products are likely to start coming into the market in July 2006.
As a policy, before publishing and publicising the results, we convey the test findings to all the manufacturers for their views and comments. They receive the results of their own products only.
Bajaj replied that the blackening of the ends had no impact on life or lumen. It also added that this could be avoided by using two anode rings on both sides but this would lead to a cost increase of at least Re. 1.
Manufacturers of Crompton and Surya did not respond till the time of going to press. Details of rating and ranking, the ‘best buy’ and excerpts of our correspondence with the manufacturers have been published in the July - August issue of INSIGHT — The Consumer Magazine.
Pritee Shah- Editor, Insight
Place : Ahmedabad
Date : 30/06/2006
The 11 brands tested were — Wipro, Surya-HBT, New Cema Super, ECE Amarjyoti, GE-Standard, New Philips Champion AR, New Crompton, Osram, Bajaj, Anchor Classic and Bengal Lamps (CM/L - 8527181).