See Also:

Power Consumption of Lights


On This Page:

My experience with CFL's

What I've done

Public Area Light Pollution



Light globes are generally rated by how much power they use (in Watts), not how much light they produce. Light intensity, measured in Lumens, is sometimes indicated on a globe's packaging. A 20 Watt Compact Flourescent light can produce about the same amount of light as a 100 Watt incandescent lamp.


The colour of the light produced is measured in degrees Kelvin. A normal incandescent light produces a yellowish 'warm' light, which has a colour temperature of around 3000 degrees K. 'Cool White' lights which attempt to approximate daylight have colour temperatures of around 5000 degrees K.

There are several types of lights widely available today. Each have their benefits & drawbacks

Incandescent lights

'Standard' light globes. They produce a yellowish coloured light. The most common ones are the standard bayonet base plain or pearl globes with wattage ratings from 25 up to 100 Watts, but are also available with different size edison screw or bayonet bases, and different physical sizes of the globes.



Halogen lights

Used as down-lights or spot lights. Some operate on low voltage (commonly 12 Volts). These lamps are commonly wired via a transformer to normal 240 Volt mains. They normally have a fairly narrow beam width, so to adequately light a room you may need quite a number of them.



Fluorescent Tubes

These are commonly available as circular or long tubes in various wattages. A ballast and starter are normally housed inside the light fitting. Alternatively, an electronic controller can be used to replace these. The most commonly available tubes produce a 'cool white' light, although tubes are available which produce a 'warm' light.



Compact Fluorescent Lights (CFL's)

Like a normal Fluorescent Light, CFL's consist of fluoro tubes and a ballast or electronic controller. There are two basic types of CFL available : One piece and two piece.

Two piece units have a separate tube and ballast. The ballasts are supposed to have a much longer life than the tubes. ie One ballast is supposed to last for about 5 tubes. Because a lot of the cost is in the ballast, these units are theoretically cheaper and more environmentally friendly. From the reports that I've heard however, the ballasts often go faulty before the first tube has given up. Two peice units are usually much longer than the one peice units making them even more difficult to fit into standard light fittings. Single piece units seem to be more readily available today.

One Piece units have the ballast and the tubes in the same unit. If the ballast happens to overheat or go faulty, the whole light has to be disposed of.

Another thing to be aware of with CFL's is that some models pre-warm the filament, while others don't. Pre-warming the filament is supposed to lengthen the life of the globe, but it also means the globe can take up to 5 seconds to switch on (which is a long time to wait when you flick the light on after entering a dark room).

Advantages :



Power Consumption

See table on Power Cosumption Tables page.


My experience with CFL's

I've tried several brands of one-piece CFLS's.

Osram: I purchased 3 OSRAM 20 Watt 'warm' light CFL's about 4 years ago. They were quite expensive -around $A30 each, but have performed faultlessly. They are not very common. One shop which sells them is 'The Cleanhouse Effect' in King St Newtown, Sydney. These lights start up quite quickly.
Mirrabella: I initially had a lot of problems with Mirrabella 15 Watt CFLS's. I returned quite a number which either didn't work from the word go, or failed within the first few hours of operation. I had more success with the 10 Watt units, with only one failure initially. One or two of the 10 Watt and one of the 15 Watt units are still functioning. They were all of the 'cool white' variety and start up quite quickly.
Nelson: They have several different models in the range. I purchased a couple of the ELM 'warm light' variety which are physically smaller than the other brands I've used, but use filament pre-warming which means they take a long time to start up. Because of their 'squarer' shaped bases, they wouldn't fit in the lamp sockets of some table lamps. I haven't been using them long enough to determine reliability over time.
Philips: I've tried a few lamps in their new Eco range. They will fit in the lamp sockets of the table lamps which the Nelsons won't fit into. They don't take long to start up, and are available in both 'cool white' and 'warm' colourings. I haven't been using them long enough to determine reliability over time.

What I've done

The previous occupants of the house I'm now living in loved roof mounted halogen downlights. Each globe is rated at 50 watts, and has its own transformer which consumes nearly 10 watts. ie Nearly 60 Watts per light. In addition to the ones described below, there are also 2 in the bathroom and 1 in a small passage area just outside the bathroom..
While I like the light that comes from these lamps, their power consumption and the fact that chunks of roof insulation have been removed to accomodate them make them a less desirable option.

Eat-in Kitchen

Before changes
were made:
??There were 4 halogen lights consuming around 235 Watts controlled by one switch. There was also a 60 Watt incandescent tube (which looked like a fluorescent tube) mounted about head height on the under-side of a cupboard above the sink, and a 15 or 25 watt globe mounted in a rangehood above the stove.

I've hung a temporary light in the kitchen, which consists of a 20 Watt Osram CFL (Compact Fluorescent Light) with a cheap white plastic shade covering it. At present this is wired back to a power point, which is conveniently located beside the entrance to the kitchen. This is proving to be quite a satisfactory replacement for the halogen lamps, and uses about 9% of the power they were using.

The lamp above the sink was very bright when you were trying to wash the dishes at night. I've replaced this with a small 25 Watt incandescent globe with a small white plastic shade around it. This provides adequate light for washing the dishes but doesn't blind you in the process.

I've also got a small desk lamp with a 15 Watt incandescent 'pilot' globe which provides light for around the telephone.

Future Plans: I'm planning to install a ceiling fan with a 22 Watt circular flourescent tube fitted to it. This will be a replacement for the 20 Watt CFL temporary arrangement. There is also one section of the kitchen which is a bit darker than I would like it. There is a disused switch beside a door in that area, so I'll probably get a wall mounted light installed there.

Lounge / Entry Area

Currently: There are currently 9 halogen lights in the lounge/entry area on two switchable and dimmable circuits. There are 4 on one circuit, consuming around 235 Watts when the dimmer is turned to max, and 5 on the other, consuming around 290 Watts again with dimmer on max.

I also have a floor lamp fitted with an 18 Watt CFL and two table lamps with 12 and 15 Watt CFL's. These provide adequate lighting 99% of the time. Normally at night 1 or 2 of these lamps would be switched on. The main reason the halogen lights would be switched on would be to look for a book in one of the bookshelves in the room.

Future Plans: I'm planning to replace the halogen lamps with a couple of 'lantern' type fittings which hang from the roof and can each accomodate a single 20 Watt CFL.


Before changes
were made:
Each of the bedrooms was fitted with a centrally located ceiling fan with an 'oyster' light fitting below it. These fittings can accomodate 2 standard sized incandescent globes, but struggle with CFL's.
Currently: I've replaced the oyster lights in two of the rooms with converter attachments which allow standard light fittings to be attached to the ceiling fans, and 19cm diameter glass ('ball') shades . These will fit a 20 Watt CFL. They do hang lower than standard oyster fittings, but this isn't a problem at my place as I have 9 ft ceilings. It may be a problem if you have lower ceilings. Each attachment and shade cost under $A30.

Desk and bed-side lamps are also used, either with low wattage incandescent globes or CFL's.

Front Porch

Before changes
were made:
As the porch roof is quite low, there is not much clearance between the light fitting mounted in the porch ceiling and the top of the outward swinging screen door. The only normal bulb that would fit in there was a small round 'fancy' incandescent globe.
Currently: I found a 90 adaptor which fits into the socket and clears the door. I've plugged an 11 Watt Nelson ELM CFL into the adaptor. This is one of the 'slow warm up' variety, and can take up to 5 seconds to produce light.


Light Pollution

Although not often thought of as pollution, the visual pollution produced by poorly designed light fixtures in urban public areas manifests itself in several ways, one of which is the wasting of large amounts of electricity that we end up paying for through council rates and taxes etc (not to mention the associated pollution).

See article on Light Pollution - Links to other sites at the end of the article.