Energy-efficient light bulbs: your shopping guide
Did you know that lighting accounts for between 5 and 10 per cent of energy costs in the typical Canadian home? No surprise, since that home is likely to contain up to 30 lamps and light fixtures of various kinds. So while heating costs are the big culprit, you should also be focusing on lighting when trying to save on energy expenses.
To reduce waste (both of energy and of money), you ideally want to use bulbs that offer the most lighting power while consuming the least energy. To help choose the ones that meet that challenge, read on to familiarize yourself with information found on their packaging.
Seeing efficiency in a new light
It used to be easy to judge the brightness of a light bulb by its power consumption in watts (40, 60, 100 W…). That changed with the advent of energy-efficient bulbs: wattage was no longer a sure-fire predictor of their light output.
Instead, the lumen—the unit that measures luminous flux, or the amount of light emitted by a source—is used. Lumens per watt, meanwhile, is the measure of the quantity of light output for each watt that is input, so the higher the lumens per watt value, the more efficient the bulb.
The table below compares the power of various types of bulb, from the classic incandescent to the latest LED models.
Lighting power and electric power of bulbs
Light output (luminous flux)
Compact fluorescent lamp (CFL)
Source: Hydro-Québec, September 2015
Other illuminating facts
While efficiency is an important purchase consideration, other criteria can make all the difference as to which type of bulb to use in your home:
Expressed in degrees Kelvin (K), a bulb’s colour temperature determines the lighting ambience in a room:
- Warm (also known as soft) white, between 2,700 and 3,000 K or less;
- Neutral white, around 3,500 K;
- Cool (also known as bright) white, around 4,000 K or above;
- Daylight, between 5,000 and 6,500 K.
Soft white bulbs produce gentle, yellowish light, ideal for bedrooms and living rooms. At the other end of the spectrum, cool white light provides the crisp illumination needed in work spaces, like kitchens and garages.
Colour rendering index
The colour rendering index (CRI) is a per cent measurement of a light source’s ability to render, or properly reproduce, the natural colour of objects. The higher the value, the better the colour accuracy. Halogen lamps, with a perfect index of 100, reveal the truest colours, while fluorescents and LEDs have a CRI of around 80 (which is still quite good). The CRI isn’t always indicated on bulb packaging, but it’s a good measure to have when selecting quality lighting.
Good to know
While the chief purpose of the Energy Star symbol on packaging is to certify that a bulb is energy-efficient, it also guarantees that the bulb has a CRI of at least 80.
If turning the lights down low to create a relaxing mood is important to you, pay special attention when buying bulbs: some of today’s energy-efficient (i.e., non-incandescent) bulbs aren’t compatible with dimmers. Before buying CFLs or LEDs, for example, check the package to make sure they’re dimmable. Most good-quality LEDs will work with dimmers, but not all. With CFLs, it’s the opposite: the vast majority are incompatible with dimmers.
Lifespan and efficiency
Further points to consider when making an enlightened purchase decision include
- the bulb lifespan, listed in hours or years;
- the manufacturer’s warranty—long-life bulbs are guaranteed for between 3 and 10 years; and
- the annual or long-term energy savings.
The last point tells you how much you can save on a yearly basis or over the entire lifespan of the bulb compared with the energy consumption of a traditional incandescent bulb. LED bulbs are the standout performers in this area: see our comparative chart for the details.
Tips for spending less to light your home
Good practices to adopt to keep lighting costs down include:
- avoiding thick or dark-coloured lampshades, which cut the light level;
- using dimmers (a great décor solution that’s also a real energy saver);
- choosing lamps and fixtures with the Energy Star logo to ensure maximum energy efficiency;
- connecting some lamps to timers if you are going to be away for a while, instead of leaving them on all day and all night;
- installing motion detectors on your outside lights;
- getting into the habit of turning out the lights when you leave a room; and finally,
- opening your blinds and curtains in the daytime to let natural light in: it’s free and pleasant!