cfl light wattage

[caveman42000]

So I have a stupid question. Do I measure the wattage as the actual amount the bulb uses or the wattage it is comparable to in an incandescent bulb? I'm going to use several spiral cfl"s that use 85 watts but give off the same amount of light as a 300 watt bulb. If I use the light amount than 3 of these bulbs would be 900 watts and plenty of light.

[DrPhoton]

Have a read of my light metric thread.

http://forum.growweedeasy.com/forum/growing-community/83013-light-metric-systems

But to answer your question, different light technologies cannot be compared with their power rating. Each technology has different conversion efficiency and light spectrum characteristics. Even when both lights have the same lumen output, the actual type of spectrum of light is usually different between technologies. The only reliable way to measure and compare between different types of lights is with PPFD. Your 900 watts would not be equivalent to 900 watts of HPS or MH. Infact it could be as much as only half the photosynthetic potential of HID's.

Any more Q's feel free to ask.

[Vapo69]

Dude its the 85w...not the 300w equivalent....you only count the actual power draw😁😁

[DrPhoton]

I think he was aware what the bulb actually draws. I believe he was questioning its light output in comparison.

[Vapo69]

Dude my apologies....I thought caveman42000 was asking if he goes off the 85w on the box, in which case 3 x 85w = 255w, or the equivalent to an incandescent bulb on the box, which would be 3 x 300w = 900w.....my mistake😀😀

[pjtt2017]

I believe I have the same question that caveman42000 had...it's about output rather than input, so to speak. This is my first grow, and I'm in the process of equipping my tent. When reading various articles about lighting, the reference is always to "x" amount of wattage that your CFL lights should put out; easy. But packages of CFL bulbs show wattage as "equivalent to..." as well as "actual". Case in point, I was looking at a pack of bulbs at Home Depot yesterday, which said "equivalent to 40 watts of incandescent" but said something about "9 watts actual"; so if I want 160 watts total output to the plants, which measurement is correct, 40 or 9? I'm assuming (unfortunate word) that the 40 watts is the correct answer, or 4 bulbs. If it's 9 watts, then I'm going to need a MUCH bigger light holder.
Thanks, guys.

[DrPhoton]

Traditionally incandescents are not used for grow lights and as such would never be a reference to for anything. When you read forums or tutorials we are referring to the wattage of the CFL light, not its equivalent.

[9fingerleafs]

let me just say, the fact that you asked instead of assuming proves you the smarter of the bunch, so dont call your questions stupid, many come around here claiming they have +999 watts with no actual idea just to add to the very informative responses while every technology is different and you cannot compare hps to cfl by wattage, we CFL growers use actual watt use to compare to one another, another way you can get closer to a fair comparison with other bulbs is using lumens, how many lummens a bulb emmits its stated on the box, so essentially adding up those values and dividing it by the space you have will give you a better way to measure actual light not electrical use.
i have 20 bulbs putting 600+ watts in a 2x4 space, so roughly at 2,000 lumens per bulb so thats 40,000 lumens divided by 8 square feet is 5,000 lumens per square feet, much more than 4 150watt bulbs would emmit, even when the wattage is the same