LED Wattage Or True Wattage 

LED grow lights for medicinal plants use have become very popular and many people are considering them for growing plants, especially for starting seedlings. It sounds like a great idea. LED lights use very little electricity so they save money, and they don’t produce a lot heat so they can be placed close to your plants. Sounds perfect and many people have started to use them with success. Unfortunately, others have found that they don’t work too well and one reason is that manufacturers don’t tell you the truth about their products. I know that is hard to believe – but it’s true, they go out of their way to confuse you.

True wattage or Draw From the Wall

True wattage is the measurement you’ll want to know to determine the actual power usage of your grow light. The actual power used by both the electrical circuits and the lights themselves – fans, etc. – are referred to as true wattage. Although true wattage is a good measure of power draw, it is not a good measure of light output because you have no idea how efficient the system is. The only true and useful measure of light output with grow lights is PPFD.LED Wattage

LED wattage is the measurement of the maximum potential power that your LEDs can handle. A light with 100 LEDs each rated at 3 watts, would have an LED wattage of 300. LED wattage is a theoretical maximum and LEDs are almost never pushed this hard in practice. Running LEDs at their maximum potential power, generate more heat and tend to burn out quickly. Therfore, LED grow lights supply less than the maximum power to the LEDs, ensuring they are more efficient.

Using True Wattage and Other Power Ratings

Each of the ratings mentioned above can tell you a little bit about the grow light you are about to purchase. The most important rating is true wattage. A setup that draws 1 000 watts of power uses 1 unit (kWh) of electricity per hour.

LED wattage can, in some cases, help you estimate longevity. For example, let’s say that you are choosing between two cheap LED grow lights. One requires 330 watts of power and the LEDs are rated at 300w. The other requires the same 330 watts of power, but the LEDs are rated at 500 watts. It’s clear that the first one is operating their LEDs at their maximum. This means that you’ll likely generate more heat, and the lights will not last as long. If you’re purchasing a high-end grow light, you don’t want to worry about this value quite as much. With high-quality components and careful engineering, LEDs can run at or near their peak performance without degradation.

In most cases, equivalent wattage is simply a marketing trick that allows manufacturers too put big, impressive numbers on their packaging. However, there are two ways you can use this value. There is a little correlation between light output and equivalent power draw, so this can be a quick way to narrow down your choices of LED grow lights. If you’re upgrading your HPS grow light, then this value can help you understand which lights will be a suitable replacement. This rating is always a rough estimate. Every manufacturer calculates it differently. At the end of the day, you’ll want to make sure you are using the correct metrics to measure the output of your lights. The correct metrics are PAR and PPFD.

What is the difference between "LED Watts" and "True Watts"?

LED diodes are rated based on the amount of power (wattage) they can theoretically handle, if they are perfectly cooled. Some LED grow light companies advertise their lights based on this theoretical wattage- we call it "LED watts". However, excessive heat generated by running LEDs at this theoretical maximum causes LEDs to degrade ("burn out") and makes them shift the color of light they are giving off, so in the real world LEDs are never run at their full rated wattage. This means that "LED Watts" is a completely useless number for comparing the light output from two different lights-- for example, you can have two "500 LED Watt" lights, with one running 100 watts of actual power through the LEDs, and the other running 300 watts of actual power.

Many companies selling LED grow lights only use the "LED watts" to advertise their lights, as the number is always larger and more impressive than the actual power draw, but it really tells you nothing about how much wattage is actually being used to produce light. The only reason we include LED light watts on our website is because so many people request it as a means of comparison (for which it is completely useless-- true wattage is the most accurate means of comparing relative power of any plant grow light).

Watts per square foot

The average LED grow light draws about 32 watts to cover 1 sq ft for flowering. Compare this to a typical HID fixture which rings in at 40 watts per square foot (assuming a  5’ x 5’ area, or 25 sq ft coverage area). Using an HID in a 4’ x 4’ will bring the power coverage up to 62.5 watts per sq ft. (The energy saving that growers can expect from using LED grow lights instead of HID is around 38%. This energy savings only takes into account to savings growers gain when using LEDs fixtures. It does not account for other environmental factors where growers can save energy. For example, less ventilation and air conditioning may be used, or foregone completely, depending on the size of the setup and ambient temperatures. Total power savings may rise above 50% in certain scenarios.)

Different LED grow lights will have different efficiencies. More efficient LED grow lights will use fewer watts to emit the same amount of light that a less efficient LED grow light will exude. Therefore, as mentioned above, wattage is not the most accurate tool to know how powerful of a grow light you need for a particular coverage area.

Quick Guide (watts per coverage area)

1' x 1': 32 watts (~30 to 40 watts)

2' x 2': 128 watts (~120 to 140 watts)

2' x 4': 256 watts (~240 to 300 watts)

3' x 3': 288 watts (~250 to 300 watts)

4' x 4': 512 watts (~500 to 650 watts)

5' x 5': 800 watts (~700 to 900 watts)

4' x 8': 1024 watts (~900 to 1100 watts)

6' x 6': 1152 watts (~1000 to 1200 watts)

Whatever the sales promotion tells you about watts – forget it. Watts tells you very little about how well a lamp will grow plants.

For most consumers, this label is far too complex. When adopted, consumers will still be confused but at least it will level the playing field. Right now manufacturers can say anything they want. Or you can give ECO Farm a go, we promise we will tell nothing but the truth.

For any further advice, pls feel free to visit our official website or contact us directly.

Our emails address is: business@ecofarm.ca

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