How Much Does It Cost to Run an LED Grow Light in the UK? (2026)
Grow lights run 12 to 18 hours a day, so wattage matters more than for any other light in the house. A small 50 watt panel for herbs is cheap; a 600 watt light for a grow tent costs as much as a fridge to run.
A typical LED grow light (150 W) costs £0.039 per hour, or about £16.58 per month at 14 hours a day in the UK. Average running cost
| Wattage | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| Low 50 W | £0.013 | £0.18 | £5.53 | £67.25 |
| Typical 150 W | £0.039 | £0.55 | £16.58 | £201.74 |
| High 600 W | £0.16 | £2.21 | £66.33 | £806.97 |
Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 14 h/day ≈ 766 kWh per year.
One hour of an LED grow light (0.15 kWh) is the same electricity as
- 3.0hours of a fridge
- 3.3hours of a laptop
- 15hours of Wi-Fi
- 17hours of an LED bulb
In the UK, with electricity at 26.3p per kWh (source: Ofgem price cap 1 Oct–31 Dec 2026, 2026-10), a typical led grow light costs £0.039 per hour and about £201.74 per year at 14 hours a day. Each £1.00 of electricity buys roughly 25.3 hours of use.
How to lower the cost of running an LED grow light
- Match the light to the canopy size. Excess light is wasted electricity.
- Use a timer so lights never run longer than the plants need.
- Choose full-spectrum LEDs over HPS or fluorescent. They produce more light per watt.
Frequently asked questions
How much does it cost to run a grow light per month?
A 150 watt light for 14 hours uses 63 kWh a month. Pick your region for the cost.
Are LED grow lights cheaper than HPS?
Yes, roughly 40 percent less electricity for the same light output, plus less heat to remove.
Do grow lights use a lot of electricity?
Because of long daily run times, yes. A 600 watt light is one of the biggest loads in a home.
Cost by region
US states
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Canadian provinces
Related appliances
- Holiday String Lights20 W typical
- Outdoor Security Floodlight30 W typical
- Smart LED Bulb9 W typical
- LED Light Bulb9 W typical
Use the generic electricity cost calculator · Which uses more? Take the quiz