Energy & Bulbs

Choosing Energy-Efficient Bulbs

LED bulb with a screw base on a plain background
A common screw-base LED bulb. Photo: Wikimedia Commons.

The habit of buying a bulb by its wattage comes from the incandescent era, when watts and brightness rose together. With LEDs that link is broken: a modern bulb can match an old one's brightness while drawing a fraction of the power. To choose well, read three things on the label instead of one.

1. Brightness is lumens, not watts

Lumens measure how much visible light a bulb produces. Watts measure how much energy it draws. Because LEDs are efficient, the wattage is low and uninformative about brightness, so the lumen figure is the number to compare. Packaging often prints a rough incandescent equivalent to ease the transition.

Rough outputApprox. lumensOld incandescent feel
Soft accentaround 450like a 40W bulb
General roomaround 800like a 60W bulb
Bright taskaround 1100like a 75W bulb
Very brightaround 1600like a 100W bulb

Equivalents are approximate and vary by product.

2. Colour temperature is Kelvin

Kelvin describes the warmth or coolness of the light. Lower numbers look warm and yellow; higher numbers look cool and blue-white. The right choice depends on the room and the mood you want.

Keep a room consistent

Mixing colour temperatures in one room is the most common reason lighting looks off. Match the Kelvin value across fixtures you can see at the same time.

3. Fit: base and shape

A bulb only helps if it physically fits. The base is the part that connects to the socket, and the shape determines whether it sits properly inside a shade or recessed trim.

MarkingMeaning
E26 / E27Standard medium screw base used in most household lamps.
E12Candelabra screw base for many chandeliers and decorative fixtures.
A19The familiar rounded household bulb shape.
GU10 / pin basesTwist-and-lock or pin sockets common in track and recessed heads.

Extra label details worth a glance

The Canadian angle on efficiency

Switching to efficient lighting is one of the simpler ways to reduce a home's electricity use. Natural Resources Canada publishes general guidance on energy efficiency and product labelling that can help frame the choice without relying on any single brand's claims.