Energy Efficient Lighting

Warts and all, here are the key facts about Compact Fluorescent Lights (CFL):

  • For the same light output, they save up to 80% of the electricity an incandescent bulb would use.
  • They last much longer, but their life varies by make and model. Additionally, longer life = reduced risk changing bulbs.
    Compact Fluorescent Lights
  • They cost more to buy, but less to run and have a lower-overall operating cost.
  • They don't work with most light dimmers.
  • They have a short warm-up time to reach full brilliance.
  • Some people think they look ugly.

So what is behind each of these claims?

Electricity Usage

Because they can use up to 80% less electricity, they are much more efficient. However, like all fluorescent lights, there is a short warm-up period before they reach operating temperature and full light output. During this warm-up phase they are not at maximum efficiency. So, if you only use them for short periods (e.g. in a toilet), then their efficiency will be less.

The package will tell you how much electricity they use; but, as noted below, things vary. A CFL lamp that is equivalent to a 100W incandescent lamp might be described as 20W or 18W. The latter might simply be more efficient, or it might put out slightly less light but as efficiently as the other, depending on the make and model.

Lamp Life

The life of a bulb is determined by its design/manufacture, and by the environment it is used in.

Incandescent lamps have been around for almost a century, so they are comparatively standardised. Standard design lives are 1000-hour and 1500-hour, though you will usually struggle to find the 1500-hour type in New Zealand. 'Design life' means that they have been designed, manufactured tested to achieve an average of the design life - due to manufacturing tolerances some will last longer than others. In a typical residential environment you will generally get the design life, but may not in hotter (down-light) or colder (external security light) situations. Reputable supermarket brands are usually 1000-hour, but be careful - "budget" or "house" brands may be built to a price rather than to a life. If the package isn't clear about design life, then "you get what you pay for".

Compact fluorescent lights are relatively new, and there is little standardisation yet. Standard design lives commonly seen include; 4500-hour, 6000-hour and 10,000-hour. However lamp life is often expressed as years, based on the lamp running for an average of 3 hours per night, so that one year is approximately 1000 hours. You may also see life expressed as so many incandescent bulbs; e.g., 6000-hours = 6 "ordinary bulbs". Finally, watch out for the words "up to" 6000 hours - this is less than an "average of" 6000 hours. When in doubt, stick to reputable brands.

A side benefit from long life is the reduced number of times someone is at risk of a sprain, concussion, broken bones, or worse, from falling while changing a bulb. For this reason CFLs are ideal for those hard-to-reach locations, particularly where elderly people are involved.

Ugly

We don't think so. CFLs are available in many styles, including those shown in the links below.

Further Information

For more information on energy efficient lighting, including tools for calculating savings, click on the links below: