How Much Does It Cost to Leave an LED Light On All Night in the UK?

The cost of running an LED light for a full night (say, 8 hours) depends on the power consumption of the light and your electricity tariff. Let's break down the costs for a typical LED light and LED strip light:

1. Power Consumption of LED Lights:

LED lights are generally energy-efficient compared to traditional bulbs. The power consumption of an LED light is measured in watts (W).

• Standard LED bulb: Typically consumes between 5W to 12W, depending on the brightness (equivalent to a 40W-100W incandescent bulb).
• LED strip lights: The consumption varies, but RGB LED strips generally consume between 10W to 20W per meter of strip. If you have a longer strip, this will increase.

2. Electricity Cost in the UK:

As of 2025, the average price for electricity in the UK is around 34p per kWh (kilowatt-hour). This can vary depending on your energy supplier and any current price fluctuations.

3. Cost Calculation:

To estimate the cost of running your LED light, use the formula:

$$\text{Cost} = \text{Power (kW)} \times \text{Hours} \times \text{Cost per kWh}$$

• For a 10W LED bulb:

  • Power (kW) = 10W / 1000 = 0.01 kW
  • Hours = 8 hours
  • Cost per kWh = 34p

  Cost = 0.01 kW × 8 hours × £0.34 = £0.0272 (or roughly 2.7p per night).

• For a 20W LED strip light (per meter):

  • Power (kW) = 20W / 1000 = 0.02 kW
  • Hours = 8 hours
  • Cost per kWh = 34p

  Cost = 0.02 kW × 8 hours × £0.34 = £0.0544 (or roughly 5.4p per night).

Do LED Strip Lights Raise the Electric Bill?

LED strip lights are much more energy-efficient than traditional incandescent or halogen lights, meaning they will have a minimal impact on your electric bill. However, the overall increase depends on factors such as:

1. How Many Strips You Use: If you use several meters of LED strip lights, the cost can add up. A 5-meter RGB strip at 20W per meter could cost you around 27p per night if left on for 8 hours.

2. Brightness Settings: If you use smart LED strips that change color and brightness, you might consume more power depending on the setting. Full brightness at full color will generally consume more power than a dimmed light.

3. Duration of Use: If you leave LED strips on for longer periods, such as 12 hours or more, the cost increases.

4. Number of Lights: If you have multiple LED strips running in different areas of your home, the total cost will naturally increase. However, compared to traditional lighting, the cost is still low.

Examples of Costs for Common LED Uses:

• 1 LED Strip (5m, 20W per meter) running 8 hours per night:

  • 20W x 5m = 100W (0.1 kW)
  • 0.1 kW x 8 hours = 0.8 kWh per day
  • Cost = 0.8 kWh x £0.34 = £0.272 per day

  If you keep this up every day for a month, that's £8.16.

• 1 LED Bulb (10W) running 8 hours per night:

  • 10W = 0.01 kW
  • 0.01 kW x 8 hours = 0.08 kWh per day
  • Cost = 0.08 kWh x £0.34 = £0.0272 per day

  Monthly cost: £0.816.

Conclusion:

• LED strip lights are relatively inexpensive to run, and their impact on your electric bill is small. Even if you leave them on all night every night, the monthly cost is still very low compared to traditional lighting.
• For a single LED bulb or short LED strip, the increase in your energy bill would be negligible (a few pence per day).
• If you're concerned about energy usage, consider dimming the strips or using them in short bursts rather than leaving them on constantly.

In summary, while LED lights do increase your electricity bill, the increase is minimal due to their high energy efficiency. Running them overnight or for extended periods won’t add significantly to your costs, especially compared to traditional incandescent lighting.