Is it cheaper to leave LED lights on or turn them off?

When it comes to LED lights, one of the key advantages is their energy efficiency. However, whether it is cheaper to leave LED lights on or turn them off depends on how long they are on and how often you are turning them off and on. Here’s a breakdown of the cost considerations:

1. Energy Consumption of LED Lights

LED lights are known for their low energy consumption compared to older bulb types like incandescent or halogen. They use significantly less electricity, so the cost of leaving them on for extended periods is much lower than you might think.

• LEDs typically use between 5W and 15W per bulb, depending on the type and brightness.
• An LED bulb can use around 0.005 to 0.015 kWh per hour.
• The average UK electricity cost is approximately 0.34p per kWh.

So, running an LED light for 1 hour would cost around 0.002p to 0.005p, depending on the wattage of the bulb.

2. Cost of Leaving LED Lights On

Let’s take a look at a common scenario where you leave an LED light on for an extended period, say 12 hours per day.

Example:

• LED Bulb Wattage: 10W (typical for a standard LED bulb)
• Duration: 12 hours per day
• Electricity Cost: 0.34p per kWh

Daily Cost of Leaving the Light On:

Monthly Cost:

As you can see, leaving an LED bulb on for 12 hours a day would cost just 1.23p per month.

3. Cost of Turning LED Lights On and Off

The main concern with turning LED lights on and off frequently is whether the power surge from switching the light on might cause it to consume more energy in the short term. However, with LED technology, the power surge is minimal, and the total energy usage remains much lower than older bulb types.

On/Off Switching Cost:

When you switch an LED light on and off frequently, the power surge is very small and usually lasts only a fraction of a second. In practical terms, the amount of additional energy used from turning an LED light on and off is negligible.

The long-term cost of leaving an LED light on for an extended period (e.g., all day) is slightly higher than the cost of turning it on when needed, but the difference is so small that it often isn’t worth factoring into your decision.

4. Break-Even Point: When to Turn Off vs. Leave On

If you're using LED lights and they are left on for only a short period (e.g., a few hours) per day, turning them off when you don’t need them will save money. In fact, the energy saved by turning them off outweighs the tiny surge in energy usage when you turn them on.

For example, if you leave the light on for 3 hours instead of 12 hours:

• 3 hours/day: 0.12 kWh per day = 0.041p per day = 1.23p per month.
• 12 hours/day: 0.48 kWh per day = 0.16p per day = 4.84p per month.

You’re saving about 3.61p per month by turning off the light when it’s not needed for those extra 9 hours.

5. Practical Considerations

• LEDs are designed to last longer with frequent on/off cycling, so turning them off doesn’t significantly reduce their lifespan.
• For rooms that are rarely used or have intermittent use (e.g., a hallway, bathroom, or guest room), it’s better to turn the light off when not in use to save on electricity costs.
• For lights that are on for long periods (e.g., security lights, outdoor lights, or ambient lighting), leaving them on is acceptable, but you may want to consider using motion sensors or timers to turn them off automatically when not needed.

Conclusion: Should You Leave LED Lights On or Turn Them Off?

• Turning LED lights off when not in use will generally save you more money in the long run, especially if you’re only using them for a few hours per day.
• The cost of leaving an LED light on is very low, but turning them off can still help reduce electricity bills slightly.
• LED lights are energy-efficient enough that even frequent on/off cycles won’t significantly impact your electricity bill or bulb lifespan.
• The best strategy is to turn off lights when not needed, especially in rooms that are used infrequently.

Overall, the extra cost of leaving an LED light on is very small, but if you’re looking to maximize savings, turning off lights when they are not in use is still the best choice.