- Brightness - Measured in Lumens
Light output or brightness of a bulb is measured in lumens. Wattage is the amount of power needed to light a bulb. Measuring the light output of different bulb types based on wattage can be misleading.
Dimmable smart LED bulbs are always a good choice as most provide more than 700 lumens and are equivalent to a 60W traditional incandescent bulb.
- Colour temperature - Measured on the Kelvin scale
Based on your personal preference, choose bulbs that provide 2700K or "warm white" light for relaxing and more than 4000K or "cold white" for work. Colour temperatures that simulate daylight are 5000K or higher.
Tip: Choose smart LED bulbs that can provide a range of colour from warm white to cool daylight. For more personalised ambience, go for smart colour-changing LED bulbs.
- Colour rendering index (CRI)
CRI measures the ability of a light bulb to accurately reproduce colours and is measured on a scale from 0 to 100. A CRI of 65 is considered poor while a CRI of 80 is considered good.
- Lifespan - Measured in hours
The lifetime of a bulb depends on the average number of hours it is in use. Bulbs that are always on will die faster than those that are rarely used.
Choose LED bulbs that have a high lifetime (average 25,000 hours). Longer life means less trouble buying and changing bulbs.
- Energy efficiency label (ENERGY STAR)
The energy label on the box shows the energy efficiency on a scale from A++ (most efficient) to E (least efficient).
These bulbs used to be the standard and for many years were the only type of bulb available. They give off a soft, warm glow similar to candlelight. Their nice ambience isn’t enough to make up for their terrible energy efficiency. Many countries no longer produce incandescent bulbs because of this. Even though they come in a wide range of colour temperatures, shapes and wattage, they have a short life span, contributing to their energy inefficiency.
The term CFL stands for compact fluorescent light. CFL bulbs function by passing an electrical current through fluorene gas, which then gives off light. This design doesn’t lose much energy to heat. Originally CFLs had a limited range of colour temperatures, but it’s been updated to include more colours. A wide range of wattages is available. They have good energy efficiency and a good lifespan. They do require a ballast to be dimmable. Like their larger cousins, disposal requires special treatment.
Standard Fluorescent Tubes
These bulbs are familiar to anyone who’s ever looked up in a supermarket or warehouse. Long glass tubes filled with fluorine gas are lit when an electrical current passes through them (just like with CFLs). They have excellent energy efficiency and very long life spans, but a terrible range of colour temperatures. Most standard fluorescent light fixtures are fitted with ballast to regulate electricity. Unfortunately, the ballast often creates an irritating buzz. Mostly associated with institutional lighting and industrial spaces, fluorescent light is rarely looked on favourably. Its best use in the home is in utility spaces (garage, laundry room, mud room, basement, etc.). Because fluorine gas is hazardous, disposal requires special treatment.