Recently I learned of a new fluorescent light that uses 125 watts of electricity and produces 8900 lumens. The lights come in two spectrums: full and red.
What is your opinion of these fluorescents?
Duane,
Kent, Washington
These lights are very efficient, high wattage, self-ballasted fluorescent lamps. They come in 90-watt and 125-watt models. The red spectrum has a color temperature of 2700 Kelvin, about the same light as produced by an incandescent bulb, but without the high amount of infrared light that is produced by incandescent bulbs. The full spectrum light is 6700 Kelvin, a blue light similar in color to sunlight at noon in early summer.
The difference between these lamps and most fluorescents is that they deliver a lot of light because they have a higher wattage than ordinary compact fluorescents, which usually use no more than 20 watts.
A 1000-watt HPS lamp delivers about 140,000 lumens initially and a 1000-watt MH lamp delivers about 110,000 lumens. That comes to 140 lumens per watt and 110 lumens per watt, respectively. A 125-watt Envirolite lamp emits about 12,000 lumens, almost 100 lumens per watt. It takes eight 125-watt lamps to make 1,000 watts. Eight Envirolite lamps emit 96,000 lumens. That's roughly 75% the amount emitted by an HPS per watt. However, that's not the full story.
The question is, how much useable light is getting to the plants? Most HPS and MH light is produced in spectrums that the plant does not use or uses relatively inefficiently. Lamps that have been improved for agriculture are only marginally more efficient, but these improvements represent a significant change in the percentage of useable light.
The Envirolite red has a spectrum with a much higher percentage of light in the red spectrum, which is the part of the light that plants use most efficiently for photosynthesis. Incandescent lights also produce a high percentage of light in the red spectrum, but they produce even more infrared light. (Incandescents are very inefficient light producers so they are the most expensive lights you can buy when you figure the cost of electricity.) When plants receive more infrared light than red light they stretch.
Plants use mostly red and blue light to power photosynthesis and use orange, yellow, and green light much less efficiently. One advantage of eight 125-watt lamps rather than a single 1000-watt bulb is that the light is distributed more evenly and there are fewer shadows.
As far as heat is concerned, the energy rating of an appliance, measured in watts, determines the amount of heat that is produced. Eight 120-watt fluorescent units produce almost as much heat as a single 1000-watt HPS lamp. It's just that it is distributed over a larger space. Watt for watt, Envirolite lamps are more expensive than high pressure sodium lights.
