Retrofitting your lighting can be a good way to save money, reduce impacts on the environment and improve light levels.

There are many types of lamp technology. Some common types include incandescent, fluorescent, and light emitting diodes (LEDs).

In incandescent lamps (common bulb) electricity passes through a filament, creating heat which in turn creates light. This is why when you put your hand on incandescent lamp, it is extremely hot compared to a fluorescent or LED lamp.


A halogen lamp is an incandescent lamp sealed and filled with gas. Typically halogen lamps are used in decorative products, such as track lighting.

Fluorescent lamps are commonly used in businesses and institutions. Compact fluorescent bulbs are mini tubes spiraled into different bulb sizes. In fluorescent lighting, electricity stimulates mercury vapors to produce a visible light. Fluorescent technology is more energy efficient than incandescent. For example, a 60 watt incandescent bulb is comparable in life and light to a 15 watt fluorescent.

There are small amounts of mercury in these lamps. You can put used CFLs in a ziploc bag and drop them off at designated CFL collection bins in some hardware stores. Tubes can also be properly disposed of through commercial handlers or onsite technologies. The mercury in a CFL bulb is lower than the mercury that would be created from electricity generation used by an incandescent bulb in our region.

LEDs create light through the movement of electrons in semiconducting material, and even longer life and higher efficiency than fluorescent lamps. They currently have a higher capital cost and the light output tends to be smaller for a comparable bulb.

When purchasing lamps, I consider factors such as lamp life, watts (measure of energy consumption), lumen output (measure of light output), and colour temperature ( measured in kelvin (K).

A warm orange light is around 2,700 K and cooler bluer lights are higher numbers like 4,000 K. If you know the amount per kWh that you are paying, listed on you power bill, you can figure out the overall cost by factoring in rated life and watts used.

When you factor this operating cost and the purchase cost you can see the difference.

Generally, fluorescent lamps make more economic and energy sense than incandescent.
LEDs last the longest on the lowest watt. There is also the capital costs, the light level and dispersion to consider.

Rochelle Owen is director of sustain­­ability at Dalhousie University. She has worked in the environment and sustainability field for 19 years;

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