Lighting Considerations –
The Race to Brighter, Cheaper, and More Efficient
When it comes to lighting considerations, remember that different types of bulbs have different efficiencies.
Couple that with your lighting goal:(a)ambient or general lighting, (b)task lighting, or (c)localized brightness (accent lighting) to highlight certain features of a room.
The news is that by 2012, incandescent bulbs must produce the same amount of lumens (brightness) for less wattage (energy). While that is an environmental benefit, compact fluorescent bulbs (CFLs) have really come down in price. In fact, CFL bulbs are replacing incandescents for the most part.
My guess is that CFLs will be phased out by LEDs once the market prices have come down to a sane level. Regardless of the outrageous first cost of LEDs, their savings, life span (25 years for a bulb) and lower environmental impact still outperform all other types of lighting.
Sidenote - Comparing high initial costs versus life cycle costs seems to be a difficult issue to bypass with energy savings technologies.
Many technologies have a high initial cost of installation, but when looking at the life span of the measure and savings compared to other conventional technologies, you still come out ahead by a long shot – if you compare apples to apples.
When considering energy savings, make the switch from simple payback mode to the life cycle cost mode. Simple payback only looks at the initial extra cost of an upgrade and divides it by the savings.
Life cycle cost considers the long term savings from fewer replacements, maintenance, impact, and many other intrinsic benefits over the life of the measure.
Should you replace ALL of your lighting with more efficient bulbs?
The short answer is that if you have the budget for it, and are looking to do a clean sweep, then go for it, you won’t have to think about efficient lighting down the line.
The longer answer is no. First, consider the location of the bulb, for example, is it in a high use area, does it get turned on and off frequently, will it be attached to a dimmer, will it experience high temperature changes and what is its purpose (general, task or accent)?
If you have a dirt basement using an incandescent light that is only occasionally turned on for say, 30 minutes a month, then a 60 watt bulb that cost $.50 with a life span of 800 hours should be fine. The bulb will last you - well, almost forever or about 133 years (6 hours per year of use) and at $.15 per kWh, will cost you $0.90 to operate per year.
As a guide to lighting considerations, replace the highest use bulbs in your house first; bulbs that will be on for 2 or more hours per day, and those that are liable to be forgotten and stay on when you leave the room.
But there are other factors to consider as well. For example, turning a bulb on and off frequently affects the lifespan of some types of bulbs more than others. Also, most CFLs are NOT dimmable (read the label before buying), and if you connect them to a dimmer switch, your power factor goes to heck.
By the way, power factor is not a lighting consideration for residential use, and you don’t get charged for it. Power factor is the ratio of the power you get from the utility is usable to the portion that is lost, say to induction, etc. Power Factor of 1 or 100% is best.
BUT, the constant low level humming from the bulbs with the dimmer switch (because of the reduced power factor) will be comparable to the Chinese water-drop torture method – and, it will also reduce the life of the CFL, as well as your hearing.
Different bulbs are also sensitive to temperature and humidity. CFLs do not like recessed light fixtures because of the heat buildup behind the can - it shortens their life.
And we all know that incandescents give off a lot of heat. In fact, only a small portion of the energy given off by incandescents is converted to light, most of it is given off in heat.
This has a definite interactive effect on your heating and cooling bills, you get a heat load reduction in winter, but you get a cooling penalty in the summer.
Keep this in mind with your lighting considerations; remember that when replacing incandescents with CFLs or LEDs, your heating and cooling needs will change also (your cooling need will decrease, while your heating need will increase).
Another lighting consideration may be the material the bulbs are made of. Compact fluorescent bulbs, for example, contain a tiny portion of mercury (about 5mg) but they still need to be disposed of at recycling and home centers like Home Depot and Ikea.
For comparison sake, a typical dental filling contains 500 mg of mercury, while a watch battery contains about 25mg of mercury. Even more to the point, the mercury used by a power plant to manufacture an incandescent bulb is 10mg, whereas for a compact fluorescent it is roughly 2.5mg. We can talk till we’re blue in the face, people don’t like mercury.
Next, some handy lighting tips, followed by the types of bulbs found in the market today and their features to help you identify the best technology for your applications:
Incandescents – If we were to replace all the incandescent bulbs in the US with CFLs right now, we would save at least 10% of the electricity needed for the residential energy market. The home sector, by the way, accounts for 20% of all the energy used in the US.
CFLs – While this technology is the best replacement for incandescents in the interim, this may become another Beta vs. VHS story all over again, or in Gen E terms, Blue Ray vs. HD DVD. Anyway, as far as other lighting considerations, it's the most affordable transition to efficiency.
LEDs – the new heros (or Blue Ray) of the lighting industry...If you build it cheaper, they will come...
Fluorescents – Still mostly for commercial use but getting popular in home use.
High Intensity Discharge – good for outdoor lighting, and some area lighting, but overall, mainly for commercial use.