LED grow light power consumption is less than conventional grow lights, and this helps to explain their popularity. However, there are a number of factors that go into their level of power consumption, and you can reduce how much power LED grow lights consume.
How Much Power Do LED Grow Lights Use?
There is not a single answer, since the power required by LED grow lights is related to how much power it puts out. Efficiency varies between models and products by manufacturers. However, in general, LED grow light power consumption is markedly less than HID or high intensity discharge lights.
A 300 Watt LED grow light will typically pull around 110 to 120 Watts of power. It is common to find LED grow lights that put out as much light as a 600 Watt HID bulb but only draw 200 Watts, a third of what the others require. A 1200 Watt LED array would consume around 250 Watts. Efficiency tends to increase with the size of the LED array, so a 2000 Watt LED grow light panel may only need 350 Watts of power.
How Efficient Are LED Grow Lights?
A standard LED light bulb needs about a tenth of the wattage of a conventional light bulb to put out as many lumens. This ratio varies based on the size and type of light bulb, with a few models achieving even better energy efficiency. However, those ratios are not as good when you’re dealing with brighter LED grow lights.
LED grow lights have become much more energy efficient over the past decade. Newer LED grow lights use half as much power as models released a decade ago. They now use, on average, 20% of the energy of conventional grow lights. Little design changes like adding reflectors to direct all the light at the plants, for example, improve efficiency by up to 30%.
One way to compare grow lights is their efficiency in visible light production or lumens relative to the power in wattage they absorb. A high intensity discharge light puts out an average of 120 lumens per watt. Some high pressure sodium or HPS lights are more efficient. In comparison, the average LED grow light generates about 100 lumens per watt.
However, this is not the only way in which LED lights use lights. For example, grow lights lose energy as receive into light. The light produced by grow lights isn’t going to be utilized 100% by the plants.
One case would be the light spectrum plants need versus what they receive. A grow lamp putting out white light is generating a broad spectrum of light, both red and blue. A mostly red LED grow light will create more red light as required by seedlings than a broad spectrum light.
Tips for Reducing LED Grow Light Energy Requirements
If you turn the lights off, they aren’t consuming power, though an active control board may still sip power. Turning off a grow light entirely via a separate timer will reduce energy usage. A grow light with a built in timer will pull some power for the control board, but you won’t forget to turn it on, either. Research how much light the plants actually need. Don’t run grow lights for 18 hours a day if the plants will grow well with just 12. You may not need to run the grow lights when there is enough natural light streaming through the window.
When LED grow lights have bulbs or chips burn out, some energy is lost at that point without producing light. The solution here is to replace burned out lights as soon as possible.
Determine how close the LED grow lights need to be to the plants to provide the right level of light. Double the height above the plants, and you cut how much light they receive by roughly half. When the bottom layers of the plant aren’t getting enough light, either prune the top or bring in smaller, targeted grow lights instead of bringing in a second, equally powerful grow light. A side benefit of this approach is that you won’t sunburn the top layer of the plant.
Pay attention to the plant’s growth stage. A plant in the vegetative stage needs up to 18 hours of light for maximal growth, but it likely only needs 12 hours for the flowering stage.