Insight - The Consumer Magazine of July-August 2005 has published the findings of its in-house comparative product testing laboratory on 7 brands of 36W tubelights.

Better Than 40W

A 36W tubelight is better than a 40W tubelight because it consumes less power, gives you more light and thus saves more money. The lighting industry, responding to the consumer’s concern over heavy power consumption, has now come up with this new, highly efficient 36W ‘slim’ tubelight.

As per the Indian Standard’s physical specifications for the 36W ‘slim’ tubelight, its maximum diameter should be 28mm against 40.5mm of the 40W tubelight. Thus, the reduced diameter, the construction differences and the gas used make 36W tubelights more efficient and better than the 40W tubelights.

What’s more, you can replace a 40W tubelight with a 36W ‘slim’ tubelight retaining the same fixture, starter, choke and all.

‘Best Buys’

We recommend Bajaj, Osram and Surya HBT 36W tubelights as our Best Buys among the 7 brands tested.

Efficiency

The tubelight that consumes the least amount of power but gives the maximum light is the most efficient one. Higher efficacy means lower energy consumption and thus lower energy bills. The ideal efficacy of a 36W tubelight is 67.36. Only one brand, Bajaj, could meet the ideal efficacy level, and go beyond. Bajaj (2425 lumens) recorded the highest at 67.57, followed by Osram (2425 lumens) at 66.86. However, the BIS does not specify this test.

Readers may recall that in our test report on 40W tubelights, only one brand came close to the ideal efficacy. In 36W tubelights, three brands came close to the ‘ideal’ level. This is one more reason for consumers to switch from 40W to 36W.

Tubelight vs Bulb

Switching from a 100W bulb to the new range of 36W tubelights, which give twice as much light output, renders a saving of about 60 per cent — a huge saving in terms of the energy consumed and the cost. And there is also the added bonus of a long life of the tubelight. Again, replacing a 40W tubelight with a 36W one will directly save 4W, i.e. Rs 40.88 a year.

Initial Lumen

Lumen is the measurement of light output. The BIS specifies that for a 36W tubelight, whose rated lumen is 2425, the initial light output should not be less than 2231 lumens; and for rated lumens of 2450, it will not be less than 2254.

This test required 15 samples of each brand. Though all the 7 brands of 36W conformed to the specification, 4 samples of Anchor Slimline (rated lumens=2425) recorded an initial lumen between 2173 and 2209, less than the specified initial light output.

However, as per the BIS, a batch shall be called non-conforming if more than 4 samples do not comply with the requirements. Bajaj (rated lumens=2425) recorded the highest range of initial lumen from 2444 to 2537 lumens.

Lumen Maintenance (Lumen after 2000 hours)

The tubelights have to not only last long but also give good quality of light so long as they last. According to the Standards, lumen ratio after 2000 hours to the initial lumen shall not be less than 85 per cent. The test required 10 samples of each brand. All brands conformed. The highest average lumen maintenance found in the 36W tubelights was 91.05 per cent in Anchor Slimline and 90.74 per cent in Bajaj.

How Long Do They Last?

As per the IS, the life of the tubelight should be 2000 hours. We have been continuing the test of tubelights for 5000 hours as per the ‘scope’ of IS 2418 (Part 1):1977, (Amendment 3). Some samples of some brands are working even after 3000 hours. The 5000-hour test will take us about two and a half years to complete.

Chokes

The cost of power consumption has always been a major concern to consumers. And if you rightly thought that just switching from a bulb to a tubelight is a good decision, there is one more option — the use of electronic chokes with your 36W tubelights.

We tested the tubelights’ ratings for the consumption of energy with electronic chokes. This test is not specified in IS 2418-1977. There is a higher saving of energy with the use of electronic chokes than with electromagnetic chokes. The purchase cost of electronic chokes is a little higher but can be recovered within about 12 months because the utilisation cost of electronic chokes is much less. (Low power consumption = less electricity bill)

Details of rating and ranking and the ‘Best Buys’ have been published in the July-August 2005 issue of INSIGHT - The Consumer Magazine.

Date : 22/09/2005 Pritee Shah
Place : Ahmedabad Editor - INSIGHT
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Annexure: Test Results of 36W tubelights (click to see annexure)
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Bureau of Indian Standards (BIS):

Tubelights are covered neither under the Quality Control Order (QCO) nor under the mandatory certification of Bureau of Indian Standards (BIS). However, since all the manufacturers went for voluntary certification and the BIS mark, we carried out the test as per the BIS Standards: BIS 2418-1977 (Part-1) with 4 amendments; BIS 2418-1977 (Part-2) with 2 amendments; BIS 2418-1977 (Part-3) with 1 amendment; and BIS 2418-1977 (Part-4).

Brands Tested:

Bajaj, Osram, Surya - HBT Slimlite, Crompton Super Saver XLR-36, Anchor Slimline, Wipro Slimlite and Philips Slimlite.