A Guide to Lighting
Light bulbs cost under £2 each, right? Wrong. The total cost of a light bulb is the purchase cost plus the cost of electricity it uses. This can be significant and varies greatly by type of bulb. Considering a house may have 50 light bulbs, this can add up to big bucks. In addition, light bulbs have a large influence on the overall mood and safety of a house. Choosing the right type of light bulb for each room deserves some thought and planning.
| Shown to the left (left to right),
incandescent, halogen, fluorescent, and compact fluorescent bulbs.
Work by passing electricity through a tungsten filament, which is enclosed in a tube containing halogen gas. The light produced is a brilliant white color which is ideal for situations requiring focus on small items such as hobbies, reading, writing, etc. A halogen bulb will last 2,000 to 4,000 hours. However, halogen bulb get much hotter than other bulbs, a 300 watt bulb may get to over 600 degrees F. Attention must be paid to placement of halogen bulb so that they are not accidentally touched and that they don’t come in contact with flammable materials (e.g. paper, cloth curtains, etc.) In addition, halogen bulbs come with a glass filter that contains harmful UV within the bulb. Be careful not to touch the glass part of the bulb, the oils from our fingers will shorten the bulb life. Halogen bulbs are less efficient that incandescent bulbs because more of the power is converted into heat.
Works by passing a current through a tube (no filament) filled with argon gas and mercury. This produces ultraviolet radiation that bombards the phosphorous coating causing it to emit light. Bulb life is very long 10,000 to 20,000 hours. Fluorescent bulbs are also very efficient, producing very little heat. Historically, there have been problems using fluorescent bulbs outside in cold environment and the light has been of poor quality (i.e. not evenly distributed over the spectrum and fluctuating over time). However, newer bulbs have much better cold weather resistance and use special coatings to provide better quality light. Fluorescent bulbs are ideal for lighting large areas where little detail work will be done (e.g. basements, storage lockers, etc.) Most fluorescent bulb cannot be used with dimmers. Note: fluorescent bulbs need components called ballasts to provide the right amount of voltage. There are primarily two types magnetic and electronic. Electronic ballasts solve some of the flickering and humming problems associated with magnetic ballast and are more efficient, but cost more to purchase.
Work like fluorescent bulbs, but in a much smaller package. Only in the last 5 years have become viable alternatives for the homeowner. Newer versions screw directly into the bases for standard incandescent lights. Similar to fluorescent bulbs, they produce little heat and are very efficient. As a rough guide:
Compact Fluorescent = Incandescent
- 4 Watts = 25 Watts
- 9 Watts = 40 Watts
- 15 Watts = 60 Watts
- 20 Watts = 75 Watts
- 25 Watts = 100 Watts
- 42 Watts = 150 Watts
Most cannot be used with standard light dimmers, although more expensive versions are available that do. Typically last for up to 10,000 hours. Compact Fluorescent bulbs are ideal for areas where a moderate amount of detail work is done, e.g. kitchens, dining rooms, living rooms, bedrooms, etc.
How to Chose
1. Depends on the activities done in the area:
– for areas of detailed work (offices, work benches, sewing rooms, etc.) choose a halogen or
– for areas of moderate detailed work (living rooms, kitchens, etc.) choose a incandescent or
– for large areas with little detail work (basements, garages, bathrooms, etc.) choose a incan
descent or fluorescent bulb
2. For areas where heat can be a problem (e.g. a small room with little ventilation) or where the bulb may be brushed against, try to avoid halogen bulbs. If possible try a fluorescent or compact fluorescent
3. Hard to reach fixtures choose bulbs with a longer life, e.g. long-life incandescent, halogen, or compact fluorescent
4. Light Colour – Try several different types of bulb. Choose the colour that provides the desired effects
5. Energy Efficiency – bulbs that are used heavily (more than 3 hours a day) consider a fluorescent or compact fluorescent. The higher purchase cost will be easily offset by the electricity savings over the life of the bulb
Halogen Bulb Chart
Note the number following the letter designation refers to the maximum diameter of the bulb in units of 1/8 inch. For example, MR16 has a diameter of 2 inches (16 x 1/8″ = 2″).