Top 10 Key Terms to Know in Lighting

When shopping for lighting, there are many terms being thrown around. From lumens to IP ratings, all this jargon can be confusing and may possibly even lead to a poor purchase. 

While you can always speak with our friendly staff here at Ozlighting to help you find the perfect light globes and fittings, it’s still important to get to know some of the basic terms you might hear in the world of lighting.

So, in alphabetical order, here’s our list of the top 10 key terms to know when you’re shopping for lighting.

1. Colour Temperature

Light is emitted in waves and colour temperature measures these light waves on the colour spectrum in Kelvin (K) which is the scientific unit for temperature.

The colour temperature of light is used to describe its redness or blueness which varies from around 2500K to 7000K. Lower colour temperatures fall on the redder side of the colour spectrum and higher colour temperatures fall on the bluer side of the colour spectrum.

This is why redder lights emit warmer light than bluer lights and why you might choose reddish light globes measuring in at around 2700K to use in your bathroom heaters, for example.

2. Illuminance

The illuminance of a light refers to the brightness of that light as it falls onto a surface. Illuminance is measured in lumens per square metre or its equivalent known as Lux.

Different from lumens themselves which measure the absolute brightness of a light, illuminance is about the brightness on a surface, meaning that as you move a light further from a surface, the illuminance or brightness of what you see on that surface will decrease.

For example, concentrated light sources like a laser can provide an intense amount of illuminance on a very small surface area. This means that lasers have a high Lux figure or level of illuminance while still having a relatively low lumens figure or absolute brightness.

3. Input Voltage

Input voltage refers to the voltage of your power source. So, if you plug in a lamp to a 240V power source, it’ll supply that lamp with 240V of power. 

You might also see an ‘AC’ next to the input voltage number when shopping for lighting which means alternating current. Most homes operate on an alternating current versus a direct current where the power source runs on a reverse flow versus a constant flow.

4. IP Rating

IP Rating stands for Ingress Protection Rating. It’s an international standard ranging from 0 to 9 that determines how protected your light fitting is to penetration by objects or water. The lower the IP Rating, the more susceptible it is to penetration by foreign substances.

Read our full blog on IP Ratings here.

5. LED

LED stands for Light Emitting Diode and they’re a type of light globe that emits light up to 90% more efficiently than incandescent lights. As the electrical current passes through a microchip, tiny light sources called LEDs are illuminated, resulting in visible light while the heat is transferred to what’s called a heat sink.

LED light globes are incredibly common and are an energy efficient way to light your home or workplace.

6. Life Expectancy

Life expectancy in terms of lighting is measured in hours. Light output and efficiency dwindles over time and the life expectancy of a light is the operating time (in hours) that it takes for the output to fall to 50% of its original lumens.

While most manufacturers label the life expectancy of their products, keep in mind, this is only an estimate as the life expectancy of a light can be further diminished by ambient temperature, supply voltage variations, number of switching cycles and other factors. 

7. Lumens

A lumen is the measure of how much light is emitted from a light globe. More lumens means the light will be brighter and fewer lumens means the light will be dimmer. 

While many people used to compare light globe wattage (or energy) when shopping for new lighting, a better way to compare the brightness of lights is using their lumens figure.

However, if you’re used to buying lights based on watts, here’s a quick watts to lumens chart to help you get roughly the same brightness this time around.




1600 lumens


1100 lumens


800 lumens


450 lumens


8. RGB Spectral Chart

All white light emitted from light globes emits some combination of the colours red, green and blue. When shopping for lighting, its colour is expressed as the individual wavelengths (in nanometres) of each colour on the RGB spectral chart. 

On the visible light colour spectrum, red light ranges from 620-750nm, green light ranges from 495-570nm and blue light ranges from 450-495nm. Similar to colour temperature, the redness of your light means it’ll be a warmer hue while the blueness of a light reflects its coolness. 

9. Wattage

A Watt (W) is the standard unit of power that specifically measures the rate of energy transfer. In terms of lighting, light globes with higher wattage consume larger amounts of energy.

Before lumens, it made sense that the more energy a light globe used, the brighter that light would be. However, that’s not always the case, especially with the advent of energy-efficient LED lights. Now, a light with a higher wattage measurement simply means that that light globe requires more power. 

10. Wavelength

A wavelength (in nanometres) measures the length of a wave from crest to crest (or the highest point of the wave). Generally, we use wavelength measurements to see where a wave falls on the electromagnetic spectrum. Visible light is only a small part of that spectrum.

Shorter wavelengths include things like UV rays, x-rays and gamma rays while longer wavelengths include things like radio waves and microwaves. Visible light waves fall between 380-700nm.

As you can see, shopping for lighting is about a lot more than just choosing between mid-century modern floor lamps and stunning pendant lighting – although choosing stylish lighting is certainly an important aspect of it all!

So, if you’re still a bit confused, no dramas. Contact Ozlighting today and we’ll point you in the right direction.