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LED Grow Lights vs. HID
Why HID Lights Look So Bright
In-house
Vegetative Growth Comparison
University of Minnesota Vegetative Growth Comparison
A number of issues determine the efficiency of a
lighting system. They include:
- Heat generated by the bulbs
- Heat generated by ballasts
- The fraction of the light used by plants
- Service and maintenance costs
When all the above are taken into account, only
about 10% of the power consumed by HID systems is actually used by plants. For a 1000-watt MH bulb, about 100 watts of
useful energy reach the plants. In contrast,
much more of the power consumed by LEDs becomes useable light.
When comparing the overall performance of LED grow
lights with HID lights, a figure to keep in mind is overall cost per yield over a 2-3
year period. This includes the initial
cost of lights, energy, ventilation, heating and cooling and the replacement cost of bulbs
and other components.
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LED Grow Lights |
Standard HID |
| Tunable spectrum |
YES |
No |
| PAR |
100% |
30-35% |
| Typical bulb temperature |
105 OF |
1,200 OF |
| Recommended minimum distance from plants |
1 inch (single color) |
24 inches |
| Service life |
50,000 hours |
20,000 hours |
| Instant restart |
YES |
No |
| Can use low voltage |
YES |
No |
| Primary spectrum output |
Red and blue |
Yellow and green |
| Fire hazard |
NO |
Yes |
| Ballast required |
NO |
Yes |
| Noise |
NO- Silent |
Yes |
Comparing Lumens
Comparing lumens from LED grow lights with that for HID lights is not a valid
comparison for gauging plant growth potential. A
lumen is a measurement of light that is based on the sensitivity of the human eye. This means that the for same amount of light
energy, green light will measure about 10 times the lumens of the blue or red light. Since
plants use mostly blue and red light, lumens are not really an appropriate index of plant
growing efficiency. We gauge the effectiveness of our lights on actual plant growth.
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