Energy Saving Lights

Energy saving lights are in fashion. Fortunately the energy savers are now mass produced and competition has pushed the prices down to a usable level. Quality is still lacking, the claims on the packets are gross exaggerations, and they may not survive in your exisitng light fittings.

Originally written in 2007 and updated to 2011.

Most energy saving lights are fluorescent tubes shrunk and twisted into a shape compatible with conventional incandescent light globes. Conventional globes use tungsten for the metal filament, the fine wire that burns bright white, and argon for the gas surrounding the filament. Both tungsten and argon are in short supply and that short supply drives the manufacturers to push us over to the energy savers, not the potential saving of electricity.

Some energy saving lights are based on LED and do save significant power but are very expensive and the light output is weak. LEDs are usually used for safety lights. One day we might have large LED panels for lighting rooms.

Some energy saving lights are based on quartz iodine lights and save only a small percentage of power compared to the cost of production.

A Short Life

Energy saving light globes cost more energy to manufacture than conventional incandescent light globes which means energy savers have to last a long time before they start saving energy. Conventional incandescent light globes burn out over 2000 hours while some extra bright white globes burn out in 1000 hours or less. The 1000 lights were originally sole as energy savers because they produce slightly more light for the same electricity but the real reason for pushing the 1000 hour light on us is to sell twice as many light globes.

The first fluorescent energy savers were designed to last only 6000 hours so the manufacturers could continue selling lots of replacements. Competition forced manufacturers to improve their products and some manufacturers released 8000 hour energy savers. Today Philips sell 10000 hour energy savers and Mirabella sell 15000 hour energy savers.

Ignore the marketing lies on the boxes. When 6000 hour energy savers were competing against 2000 and 1000 hour conventional light globes, the 6000 hours was promoted as 8, 10 or 12 times longer life. How can 6000 be 12 times more than 2000 or 1000?

ECO lite

Update July 2010
ECO lite is the only brand on an energy saving light I used in a storage area. The model id is SF 810 B-20W. The light was one of several trying to illuminate every corner of the space. There was no dampness or heat in the space to shorten the life of the device. Usage was one or two days a week for one to four hours. Average five hours per week multiplied by about 40 weeks per year multiplied by less than three years, you get less than 600 hours of use then it stopped working. A standard incandescent light lasts 1000 - 2000 hours, uses less resources to manufacture, and there is no mercury to clean up afterwards.

One out of four fails

Update July 2010
Standard incandescent light globes fail early in about one out of ten cases. I find energy saving light globes fail in one out of four cases for everything except the most recent globes from some better manufacturers. Plus there are additional failures when the glass cracks while you are inserting the globe. Many of the energy saving light globes need far more packaging to protect them during shipment. Some light fittings will have to be redesigned so you can hold the base of the energy saving light globe, when inserting a new globe, to stop all the failures from glass breakage.

None reach their stated life

Update July 2011

I was one of the first home owners around here to convert many lights to energy saving CFL, Compact Fluorescent Light, globes. The manufacturers claimed from 6000 hours to 15000 hours. Many have failed. None has reached 6000 hours. One might have reached 4000 hours. That is only one out of 30. A small number are close to 2000 hours or the same life as a conventional light globe.

Some of the new CFLs have warnings against using them in conventional light fittings because a 15 watt CFL produces almost as much heat as a 60 watt conventional globe and the CFLs are far more sensitive to heat. So now we are looking at replacing a $0.60 conventional globe with a $5.00 CFL plus the $50.00 ~ $250.00 for the new light fitting plus the new light fitting is open to dust and insects, meaning we will have to clean the light fitting every week instead of one every few years. Using one office here as an example, the conventional light globe lasts 2.3 years and the enclosed light fitting is cleaned only when the globe is replaced. A CFL will still have to be replaced every 2.3 years plus every week the cleaner will have to climb up a step ladder to clean the light fitting.

Not That Bright

The front of the packet tells you how bright an energy saver is compared to a conventional incandescent light. The packet in front of me says the enclosed 18 watt energy saver is equivalent to a 90 watt conventional light. A competing brand says their 18 watt light is equivalent to a 100 watt conventional light. Tests show neither light appears as bright as a 90 watt light and both are not much brighter than a 75 watt conventional light.

In the early days of energy savers, there were brands claiming to use just one eight the amount of power compared to conventional lights, just 12.5 percent of the power or a saving of 87.5 percent. The exaggerations and outright lies are still around but the major brands have reduced the degree of exaggeration. I find a 15 watt energy saver comfortably replaces a 60 watt conventional light for a saving of 75 percent.

Mirabella claim 80 percent saving. Your result will depend on your room. White walls reflect red and green light better than blue. Wood and red brick walls reflect red light, a little green light, but no blue. Conventional incandescent lights have lots of red and green to reflect around your room giving an even light. Energy saving fluorescent lights produce a lot of blue light that is soaked up without lighting up the room, leaving you to turn on extra lights to make up the difference.

Buy a few lights and try them. You might find the Mirabella 80 percent saving true in a laundry where all the walls are covered with white plastic cupboards that reflect the blue light, and an 18 watt energy saver is a bright as a 90 watt conventional light. In your Jarrah lived study with all that rich warm reddish brown wood, the 18 watts of bluish energy saving light might be less effective than a 60 watt conventional light.

My office is mostly white paint with some almost white pine and several shelves full of books with blue and black covers. In that space, 15 watt energy savers are not as bright as 60 watt conventional lights and 18 watt energy savers are a little brighter than 60 watt conventional lights.

Update July 2011

The CFL packet in front of me says the enclosed 12 watt CFL replaces a 60 watt conventional globe then the back of the packet says this globe has a very short life compared to other CFLs. That sounds exactly like a conventional globe where brightness is a trade off against life.

The 12 watt CFL is brighter than some brands of 18 watt CFLs. I tested the brightness when reading books. The 12 watt CFL is not as bright as the 60 watt conventional globe it replaced. I had to add a second CFL to get equal brightness. Two of the 12 watt extra bright sort lived CFLs equals a 60 watt conventional light for real life reading tests. That is 24 watt advertised power. Allowing for the power factor correction mentioned in the comments below, the CFLs are actually using 48 watts of power. 48 watts of CFL equals 60 watts of conventional lighting.

Use Lots Of Little Lights

In my office, I have one central light on the ceiling and four desk lamps around the room to throw light into the shelves. I can switch the desk lamps on when needed for a specific shelf and off when not needed. This saves energy no matter what type of light globe I use in the lamps.

If all the lamps were on, the light in the room would be equivalent to the light in a typical office where strong overhead lights are used to burn into dark spots in shelves and cupboards.

The high central light, on the ceiling, places light on my desk for reading books and does not reflect off my computer screens. Each desk lamp is on a shelf pointing at nearby shelves. The central light uses 40 percent of the electricity and each desk lamp uses 15 percent of the electricity. I never have all the lights on at the same time because the only time I look in all the shelves is during daylight when I use free sunlight.

On average, I use no lights during the day because the while paint reflects sunlight around the room. At night I use the central light plus only one or two of the desk lamps, for an evening average of 55 or 70 percent of the maximum power. I get up early to use all the sunlight and work twice as many hours during the day compared to night. That makes my average daily usage between 18 and 23 percent of the power used in a typical office.

No matter what sort of lighting you use, you can switch off some of the overhead lighting by using small lights focused into the dark spots. You can switch the local lights off when not in use and most of the local lights will be off most of the day.

Capital Cost

A standard light globe costs $1 in our local shops and energy saving light globes used to cost $15 to $20, a bad deal. The energy savers lasted as long as three of the standard light globes. Paying $20 to replace $3 worth of standard light globes is a bad deal plus the energy savers did not save energy when you consider the energy used to make the energy savers.

Now we can get a pack of two energy saving light globes for $9.95, which is $4.97 each. The new energy savers last as long as seven conventional light globes, $7, helping the new energy savers save $2.03 before you count the electricity.

Running Cost

Energy saving light globes used to cost up to $19 more than a conventional light globe and, over their short life, saved only $1 on electricity. Paying $19 to save $1 is a bad deal.

The new energy savers last as long as seven conventional light globes save $2.40 of electricity over that time, helping the new energy savers save a total of $4.43.

Dimmers

You might have dimmer switches fitted to some of your lights. The dimmers turn down the power to conventional incandescent lights to give you a soft glow similar to candle light. Dimmers let you control the light in a room and save electricity. Energy saving lights do not work with dimmers.

How do you control the light with energy savers? Instead of one big light with a dimmer, you can use lots of little lights with separate switches and switch on only the lights needed to produce the right mood. You can also change the light by using energy savers with different colour temperatures.

Colour Temperature

Energy savers usually produce light at a colour temperature of 6000 degrees, the same colour light as sunshine at 10:00 am in Sydney during summer, far too bright and white for a romantic dinner. Manufacturers can change the colour of the light from their energy savers by changing the mix of chemicals that coat the inside of the glass tube.

6000 degrees

What does 6000 degrees look like? Your computer monitor, when new and turned up to maximum brightness, blasts out a bright white light close to 10000 degrees or the colour of midday sun in a Sydney summer. Most people run with their monitor turned down a touch, producing a brightness closer to 6000 degrees. 6500 degrees is often the target colour temperature for screens used to edit photographs.

CRT style monitors can easily blast your eyeballs back through your head with excess brightness. LCDs have a hard time with brightness because the LCD display is a set of filters in front of a white panel and the final image is never as bright as the underlying white electroluminescent panel.

When you compare several 6000 degree lights to one 10000 degree light, the 10000 degree light look slightly blue. When you compare the other way, several 10000 degree lights to one 6000 degree light, the 6000 degree light looks slightly pink and you feel your eyes straining in the 10000 degree light. This paragraph is set to look like 6000 degrees against the 10000 white of your monitor, assuming you have your monitor turned up to full power.

2700 degrees

Some lights are labelled warm white and have lower colour temperatures. My favourite brand sets their warm whites to 2700 degrees, which is softer than incandescent lights and close to the brightest candle light, but not as good as dimmed incandescent lights or candles. 2700 degrees is good for rooms next to the romantic dinner but stick to candles for the dinner table. This paragraph looks similar to 2700 degree light on my screen.

When you change to multiple small energy saving lights with separate switches, make some of the lights warm white to provide a variation. 2700 degrees is a touch to warm for reading. The ideal replacement for incandescent lights is a mixture of one 6000 degree energy saver with one or two 2700 degree warm whites.

3500 degrees

6000 degrees is too harsh for a restful read, 6000 degrees is wake up, go to work white. One day we might get lights around 3500 degrees for reading, the late afternoon colour temperature of sunny Sydney summer sunlight. Until there is a wider choice of colour temperatures, you might like to keep one reading lamp fitted with an incandescent light just for that restful late night read before going to sleep. This paragraph is set to appear around 3500 degrees on my screen.

I found one brand of energy saver branded as cool day light at 4100 degrees. I think they mean day light in a cloudy country or in the north of North America, certainly not daylight around Sydney or most of Australia.

Colour Accuracy

You want accurate colours for photography and for editing images. All fluorescent lights, including the energy savers, are notorious for producing inaccurate colour. They have peaks in their colour range and many have parts of the range missing. Incandescent lights have a natural colour range that is well known and consistent. You can get film designed for incandescent light but nothing works with fluorescent lights. Your digital camera has an accurate setting for incandescent but any setting labelled fluorescent is pure guesswork.

When you edit images and try to compare the colour on the screen to a colour on your desk, you want your room lit to the same colour temperature as your screen and you want the same even colour spread. Go to a professional photography supplier and get lights with an even colour spread at a known temperature. The current international standard recommends D50 lighting at 5000 degrees and is used with a screen set to 6000 degrees.

All lights change colour with age. LED lights have the least colour change but you need many to get decent light. All lights change colour as they warm up and LED lights are the only lights to reach a stable colour quickly.

Colour Trick

Look at the red square for 30 seconds then move your eyes a little to the right. You will see a bluish square on the white area.

Your eyes detect colour using a slow chemical reaction. When your eye receptor cells are drenched in one colour for a while, the cells become less sensitive to the colour and more sensitive to the other colours. You cannot tell what colour a room light is after looking at the light for more then a few seconds.

Eye strain from poor light and bad colour balance starts to give you a headache after a few hours. Strain free vision is far more important than the small amount of energy one light globe might save compared to another. A small saving on one light globe is useless when you have to turn on a second light globe to clearly see your work.

When testing room lights, test for a couple of seconds then go outside into sunlight to rebalance your eyes. Repeat the test several times and have other people try the same test. Perform the test when the sunlight is most comfortable which may be early am in summer and midday in winter.

The next test is to work in the light for a normal 10 or 15 hour day without moving out into the sunlight, opening a window, or anything else to rest and recharge your eyes. If you room lights survive both tests, you have the right light.

Conclusion

Replace your conventional incandescent light globes with the new quite long life energy saving light globes except where you use a dimmer. Consider replacing a dimmable lights with multiple smaller energy saving lights controlled by independent switches. Use lots of optional switchable lights for dark corners and never risk your eyesight just to save electricity.