Electricity Saving Tips For Homes And Offices

Are CFLs replacements for Tube lights?

By on April 26, 2018

We have all known that CFLs are great electricity savers as compared to incandescent bulbs. Years of campaign and successful marketing by the government have led to good penetration of CFLs in Indian market, which is great. Although it is good that we have adopted CFLs so well, but CFLs were supposed to be replacement of incandescent bulbs. Are you using it to replace tubelights?

Fluorescent Lamp Technology

Both CFLs and Tubelights use the same Fluorescent Lamp technology to produce light. It contains mercury and phosphorous, particles of which get excited to produce light when current is passed through it. It requires a ballast or choke to pass current through it.  Traditional incandescent lamps waste 90% of electricity they use as heat and convert only 10% to light. Fluorescent lamps do not waste electricity as heat

Difference between CFL and Tubelight

CFLs are point source of light where light originates from the center (or point) and radiates outside in circles as shown in the diagram below:Point Source

The light is stronger at points closer to the center, but points farther away from the center get much lesser light. So closer you are to the bulb, brighter you will feel, but farther you are from it, you will feel less light.

Tubelights on the other hand are line source of light. Their light radiation pattern is cylindrical in nature as shown in diagram below:Line Source

Tubelights cover more area with bright light as every inch of a tubelight acts as a point source. This makes one feel that a room with tubelight is brighter than a room with CFL.

So if you compare a 28 W CFL with 28 W tubelight in a bigger room (with wider area), you will feel that the room is brighter with 28 W tubelight. The reason for it is as explained above.

So where should you use CFL and where a Tubelight?

CFLs are great for smaller areas like puja room, kitchen (if it is small), bathrooms, etc where the light requirement is less.  For bigger rooms like drawing rooms and bedrooms, a tubelights are better. Tubelights are also better for tasks like reading, studying and sewing that require much more brightness.

Is it better to use multiple CFLs instead of a tubelight?

It depends. If you use all the CFLs at same time then the total wattage may be more than the wattage of a tubelight. But if you use only one CFL at a time, then the total wattage will be less than a tubelight. Also please note that to get the brightness equivalent to a tubelight, 3 or more CFLs will be required in the room, which will make the wattage requirement more than a tubelight.

Which tubelight is the most electricity efficient?

Tubelights come in 3 variants:
T-12, T-8 and T-5 with diameter of 38 mm, 25mm and 16 mm respectively. The table below gives a comparison of all these variants:


Power Rating

Ballast Type available

Power Rating with Ballast


40 Watts

Electromagnetic (15 Watts)

Electronic (3 Watts)

55 W (electromagnetic)

43 W (electronic)


36 Watts

Electromagnetic (15 Watts)

Electronic (3 Watts)

51W (electromagnetic)

39 W (electronic)


25 Watts (for 4 ft long tube)

13 Watts (for 2 ft long tuble)

Electronic (3 Watts and 1 watt for 4ft and 2ft tubes respectively)

28 W (for 4 ft long tube)

14 W (for 2 ft long tube)

T-12 is the most inefficient version of tubelight and is being phased out in many countries. But it is still most commonly available in India.

T-8, which is slimmer than T-12 has been used as a replacement of T-12 for quite some years now. It can be installed in the same fitting as that of T-12.

T-5, which is the most efficient one is the latest and best tubelight available in Indian market currently. It is very slim and cannot be fitted in a T-12 or T-8 fixture. It comes along with it’s own fixture. So if you plan to replace your tubelight with T-5, then you will have to change the complete fixture to this slimmer one.

Below are the 2 types of ballasts that tubelights use:

Electro Magnetic Ballast

Electromagnetic Ballast with a choke

Electronic Ballast

Electronic Ballast

How to choose the right CFL?

Always look for the size of the room before choosing a CFL. Choosing a 28 Watt CFL for a very small room is wastage of electricity if you use that room only for storage. At times a 5 watt CFL is also sufficient for a bathroom and by using 28 Watts CFL you are putting a strain on your electricity bills and increasing units consumed. You are the best judge to evaluate the brightness required in a room, so please make sure that you choose appropriate CFL. You can also check our article on task based lighting and CFL buying guide to get more information.

Where can I get a T-5 tubelight?

The best bet is your closest electrical store. Ask for a T-5 tubelight and you should get it. In bigger cities they are also available in bigger retail stores like Home Town, etc. Phillips, Havells, Osram and Surya are some of the big manufacturers of T-5 tubelights. A T5 tubelight costs around Rs 450 and can payback for itself (by saving electricity) in a year or so. T5 tubelights have a life of 4-5 years and come with 1-2 years replacement guarantee.

The intent of this article is not to take away merits of using CFL. CFLs are great electricity savers. What we want to highlight is that it is important to choose the right kind of lamp to make sure that you needs are met and electricity is saved. Keep watching Bijli Bachao as we are in process of creating a calculator that can help you evaluate different types of lighting options with money savings.

Source of Photo and Information:



About the Author:
Abhishek Jain is an Alumnus of IIT Bombay with almost 10 years of experience in corporate before starting Bijli Bachao in 2012. His passion for solving problems moved him towards Energy Sector and he is keen to learn about customer behavior towards Energy and find ways to influence the same towards Sustainability. .

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