How much does it cost to run a light bulb?

If you want to keep your energy bills down during the dark winter months, you’re going to want to know how much it costs to run a light bulb

Large exposed wall mounted lightbulb
(Image credit: Getty images)

If you’re trying to cut down on energy usage at the moment, then you may have asked yourself ‘how much does it cost to run a light bulb?’ Especially if people in your household have a tendency to leave them on when not in use. 

After all, we are well into the winter period when our energy use ‒ including our reliance on additional lighting ‒ is at its highest. 

What’s more, with the cost of energy being double what it was last winter, turning the lights on less frequently is likely going to help you to cut energy costs and the size of your eventual energy bills. 

So it’s a good idea to know the different types of light bulbs and how much they cost to run.

How much does it cost to run a lightbulb?

How much it costs to run a light bulb depends on a few different factors, such as its wattage.

The wattage of a light bulb essentially outlines how much energy is used in order to light it.

There are also different types of light bulbs, the most common being:

LED light bulbs

The most efficient light bulbs of them all. LED bulbs use between four watts and 18 watts. According to Energy Saving Trust (opens in new tab), if you switch from a high-energy light bulb to an LED one, based on 562 hours of running time over a year you could save up to £15 per bulb, per year. 

Compact fluorescent lamp (CFL) light bulbs

CFL light bulbs use between six and 22 watts. CFL bulbs are four times more efficient than a high-energy light bulb and they typically use 60-80% less energy. 

High-energy light bulbs

These are also known as incandescent bulbs and they use up to a whopping 100 watts, while halogen bulbs use up to 120 watts. These are being phased out and are harder to find. 

Energy Saving Trust (opens in new tab) generally recommends LED or CFL lighting for indoor and outing lighting. If you have spotlights, dimmable lighting or a crystal chandelier, they recommend LED bulbs or spots. 

According to Uswitch (opens in new tab), the cost of using an LED bulb works out at around the following: 

  • Cost per use (one-hour running time): £0.003
  • Cost per year: £0.18

What should I look for when buying a lightbulb?

If you want to cut the cost of running your light bulbs, and therefore save on your energy bill, there are a few different features to look out for.

Energy efficiency rating

First and foremost, it’s a good idea to check the energy efficiency rating of the light bulb. Newer light bulbs have an energy efficiency rating, ranging from A+++ for the most efficient and G for the least.

The label energy efficiency rating label on the light bulk packaging will outline not only the rating itself, but also how much energy the light bulb consumes when used for 1,000 hours.

Smart connectivity

The days of relying entirely on light switches for turning our light bulbs on and off are behind us, with the increasing availability of light bulbs that can be controlled via an app such as Hive or Hue. 

These can be useful options if you are looking to save energy and reduce your bills ‒ you can use the app to turn lights off even if you are not in the property, while you can also set them to turn off automatically at specific times, such as sunrise.

Low wattage

Low wattage bulbs, by their very nature, use less energy. So it pays to consider the needs of the specific room where the light bulb will be used when determining what sort of light bulb is required.

The table below from the Energy Saving Trust compares the wattage of traditional bulbs with the approximate equivalent lumen values of LEDs and CFLs.

Swipe to scroll horizontally
Traditional bulbLED/CFL bulb
15 watt140 lumen
25 watt250 lumen
40 watt470 lumen
60 watt800 lumen
75 watt1,050 lumen
100 watt1,520 lumen

How to cut the running costs of a lightbulb

No matter what type of light bulb you own, you can cut its running cost by following these simple steps:

If you leave the room, switch it off 

Ben Gallizzi, energy expert at Uswitch (opens in new tab) says: "Turn the lights off when you leave a room - this is a significant source of energy wastage and could save you £20 per year.”

Keep it clean 

Ben also points out the importance of regularly dusting your lights.

He explains: "If dust dims the brightness of the bulb, this could lead to you using lamps or other forms of lighting to brighten the room further, therefore using more energy.”

Make the switch to an energy-efficient light bulb

Moving from a high-energy bulb to an LED bulb can save you around £15 per bulb over the course of a year, a saving that cannot be sniffed at. They can be a more long-lasting solution too, according to Ben.

“LEDs in particular use a quarter of the energy of incandescents and can last up to 25 times longer.”

Don’t forget about outdoor lighting 

“For exterior lighting, use halogen lightbulbs - they consume around a quarter less electricity than incandescent bulbs without any reduction in brightness,” concludes Ben.

Vaishali Varu
Staff Writer

Vaishali graduated in journalism from Leeds University. She has gained experience writing local stories around Leeds and Leicester, which includes writing for a university publication and Leicester Mercury. 

She has also done some marketing and copywriting for businesses.

When she is not writing about personal finance, Vaishali likes to travel and she's a foodie.