Power: one of the key criteria when choosing an LED bulb
For any electrical component, lighting devices included, power is a fundamental value. It measures the amount of energy consumed per second for the device to work properly. In the past, it was the favourite benchmark for choosing incandescent bulbs, because the more powerful the bulb, the more light it gave off. Today, that is no longer the case, especially as LED bulbs produce far more light for the energy they consume. Even so, the power of LED lamps remains an important criterion for combining comfort and energy savings.
What does LED bulb power actually mean?
It is measured in watts (W) and indicates the amount of energy an LED bulb consumes to work properly. For a dimmable LED bulb, the power shown in its specifications corresponds to the amount of electricity consumed when the light output is at its highest.
A bulb's power is also linked to other indicators that show why it matters. These include:
- the LED bulb's consumption;
- the amount of light emitted, or light intensity;
- luminous efficacy;
- the energy label.
Identifying the right power for your LED bulbs means choosing energy-efficient bulbs that optimise your lighting system's consumption while providing the right level of light for visual comfort in the room concerned. It's good for you and for the planet!
What is the difference in power between LED, halogen, incandescent and compact fluorescent bulbs?
From one technology to the next, the way bulbs work has changed a great deal, and the power needed to run them has come down. From the first incandescent bulbs to LEDs, electricity consumption has fallen sharply while bulbs' luminous efficacy has risen.
On average, we get:
- a luminous flux of 12 lm/W for an incandescent lamp;
- 20 lm/W for halogen bulbs;
- 60 lm/W for compact fluorescent bulbs;
- 100 lm/W for LEDs.
For the same amount of light, a powerful LED bulb uses on average 10 times less energy than an incandescent lamp, or half as much as compact fluorescent lamps. Of course, these differences can vary depending on factors such as the shape of the bulb and the quality of its manufacture. Even so, they allow power equivalents to be defined when switching to LED.
An example: to light a room needing 1,200 lumens, you can replace 4 incandescent lamps of 25 W each with 4 LED lamps of 3 W. The total consumption of your LED lighting system will then be 12 W instead of 100 W.
What bulb power for which type of space?
To find out which LED bulb power to choose, you first need to identify the lighting needs of each of your rooms. To do this, we use illuminance, expressed in lux (lm/m2), which defines the amount of light needed per unit of area, and then work out the corresponding bulb power. Lighting needs obviously vary from room to room, depending on how you use it and the visual comfort you want.
The light output needed in the bedroom
This haven of peace needs a soft atmosphere that helps you relax and fall asleep. That means around 100-200 lux (lx) for the main lighting. In a 20 m2 bedroom, 2,000 to 4,000 lumens are needed. To achieve this, the combined power of all the LED bulbs installed should be between 20 W and 40 W. In this room, screw-cap LED bulbs with an E14 or E27 cap are generally used.
Light intensity in your living room
This room has many uses. You use it to read, work or simply enjoy a relaxing evening, so lighting needs vary a great deal. For a 1 m2 reading corner, for example, a table lamp needs 3 W of power to provide the minimum 300 lux required for reading. In the living room, you can opt for designer LED bulbs, such as filament bulbs.
Bulb power in a kitchen
A well-lit kitchen needs around 500 lux for the worktop. That is around 20 W of power for the LED bulbs installed above a 4 m2 kitchen island where you prepare all your favourite dishes. For general lighting in the rest of the room, allow 300 lux on average, which means 48 W of power for a 16 m2 kitchen. Small kitchen fittings only need a pin-cap LED bulb.
In the bathroom
The bathroom, a temple of beauty, needs 200 lux for general lighting and up to 500 lux to light the mirror and washbasin area. For this specific area, you will need an 8 W lighting system for a surface of around 1.6 m2. For bathroom spotlights, choose GU10 LED bulbs.
What LED bulb power for a hallway?
As a place people mainly pass through, the hallway does not need much lighting. At least 100 lux is needed, which means a total of 6 W of power for LED bulbs lighting a long 6 m2 hallway. To decorate the hallway, you could for example choose LED pendant lights for E27 LED bulbs.
Ideal lighting for stairs
Like hallways, stairs are places people pass through, where good lighting is essential to avoid tripping on the steps. Lighting of at least 100 lux is also recommended. That corresponds to around 9 W of LED power for a 9 m2 staircase. You can choose to install small E14 LED bulbs all the way up the stairs.
In the garage
As well as protecting your car, the garage can also serve as a storage room for tools or a workspace for DIY. In the latter case, the workbench lighting should provide between 300 and 500 lux. That means lighting with a power of between 9 and 15 W for a 3 m2 area. For a large garage, you can opt for a large LED bulb, such as the E40 LED bulb.
What is the power range of the different types of standard bulb?
It is one thing to identify the LED bulb power you need for your lighting. It is another to be able to fit these LED bulbs into your existing lighting system. To do this, knowing the power of LED bulbs by type can be very useful, either to select lamps with suitable caps for the power you want, or otherwise to change the lampholders in your lighting system.
Here are the LED lamp power ratings available by cap type:
- E14 LED bulbs: 4 to 12 watts.
- E27 LED bulbs: 1 to 200 watts.
- E40 LED bulbs: 80 to 160 watts.
- GU10 LED bulbs: 6 to 15 watts.
- G9 LED bulbs: 3 to 7 watts.
- G4 LED bulbs: 2 to 4 watts.
If E27 LED bulbs come in such high power ratings, it is because their cap is the most common in homes today, perhaps even in yours. This available LED power range is a real plus: it lets you easily replace your traditional bulbs for a smooth transition to LED.
