There is a love affair that most people have with the familiar incandescent light bulb. Also known as the tungsten, it delights us with its cosy agreeable light and atmosphere, soft on the eye, warm on the heart. We love it, but have never realised until we might lose it. With this traditional light bulb we know what to expect, we know where to use it and don’t mind buying one at an inexpensive R4.50.
Apart from this, what else does it really do for us?
In the half year that this tungsten delights us in our home it will probably have clocked up 10 times its purchase value on our electricity bill: A 60W light bulb burning only 3 hours per day over ½ year consumes 32.4kWh. Combined with the new electricity tariff of R1.34 typical for a middle income household the energy costs are 44 Rand to the homeowner. To the planet the costs are 33.7kg of carbon dioxide emissions into the atmosphere. Can you imagine what the 8 down-lighters (50W each) above the dining table consume and pollute over ½ year? Yep, they cost the homeowner 294 Rand in electricity and cause 227kg of CO2. The reasons for the high running and environmental costs, is that all tungsten and halogen light bulbs convert 80-90% of the energy consumed into heat, and only the rest into visible light.
Mmh – high cost for us, high cost for the environment, not really in our favour, is it? It appears to be a rather one-sided love relationship with an unsustainable future… Maybe it is time to say good-bye to the good old incandescent and embrace what is new, more efficient and thus green. Generally, where there is a door closing there is another opening. What lies beyond that door is a challenge for us to explore more efficient options and to reconsider the where and how we use light.
Many of us have heard of CFLs (compact fluorescent) and LEDs (light emitting diodes). I am very well aware that some of them have their drawbacks and that they will challenge our perception on what light should look like and how much a light bulb should cost. But on the other hand since most of us have tried our very first CFL and decided promptly that this was not for us, the industry has moved on to give us more agreeable shades of warm light colours and better looking shapes and sizes. Some of them are now dimmable and suitable for outdoors.
So, the industry has moved on and it is time for us to move on, too. We need to balance the qualities of a light fitting and its bulbs carefully. Light bulb buying won’t be as easy as choosing between 25W to 100W any longer and herein lies our challenge. We need to consider these 5 aspects of light quality first and then make an informed choice:
- Watt (W) is the energy a light bulb consumes.
- Lumen (lm) is the light emitted as perceived by the human eye.
- Colour Temperature
- Colour temperature (K) is measured in Kelvin and ranges from 2500K to 4000K for residential purposes. The lower the figure is in Kelvin, the warmer the colour.
- Luminaire Housing
- Luminaire housing is the trade’s term for lampshade, ie the form and transparency of a light fitting. Its design matters for the light output.
- Each light has a purpose.
The above 5 aspect are of course all interrelated and have to be considered when choosing a light bulb. So, when you are ready to say good bye to your incandescent light bulbs and keen to explore new options, equip yourself with a list of your light fittings and their 5 aspects. You’ll probably find that gradual change is more agreeable. Changing all the light bulbs from one day to the next will likely be a bit of a shock for your eyes as well as your budget. If your home transforms over time, your family will have time to adapt and to understand the 5 aspects much better. It will also show you which new bulb works for you and your style. Get to your local electrical shop or DIY warehouse to see what light bulbs are available. Don’t be shy to ask them for their LED or CFL catalogue. Maybe the bulbs specific to your needs can be ordered. Also remember that a well chosen energy efficient light bulb will pay itself off over the next months or year.