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possible great deal on 4' T5 HO?

holy moly that looks sweet
 
I've been considering a foray into T5s, but I don't really know for sure...
Someone convince me its a good idea?
 
Yep, that's a pretty good deal. Here is a 4 bulb, 4' fixture, wired w/4 bulbs and your choice of color spectrum for the same price. There is also a 2' model for about 1/2 the price of the 4', but it doesn't include shipping.

Phiss, here is a little math. It takes about 14, 4' bulbs to equal the lumens output of 4, 4' T5's. So, 7 standard fixtures @ $9.ea is $63 (and that's the cheapies)+ 14 bulbs @ $3.50ea (for 6500K) is $49. Total of $112 + a $8 power strip to plug them all into totals $120 for the 7, T12 or $130 for the 1, T5. Now, try to put 7, T12 fixtures over a 55gal terrarium...LOL! The T5 light because it's more concentrate, I believe, is supose to penitrate deaper/farther from the bulb/source also than the T12 bulbs. Then there is the power usage factor. 14, 40watt bulbs is 560watts whiel 4, 55watt bulbs is only 220 watts, less than 1/2 the power consumption.
Convinced?
 
yeppers that is a less expensive alternative, one needs to compare the individual pros and cons carefully..

Av
 
One thing that kinda irks me, is when people compare power costs over an amount of years. Honestly, if I save $13 over the course of 5 years with a T5 as compared to a T12.....I really don't care. It's $13. If someone can show some REAL savings (please do the math, cuz I'll embarass myself) past the startup costs, showing that T5s are more economical, please do.
 
OK, let me look at the math. I think it will be a bit more that $13 over 5 years...
1 kWhr (1000 watts for 1 hour) cost about 10 cents. I'll use a 14 hour light cycle for 365 days a year. That would be like 6 months @ 12 hrs a day and 6 months @ 16 hrs a day.
So with that in mind, T12's first.
560 watts x 14 hrs = 7.84 kWhrs (7840 watts) or 78.4 cents a day.
78.4 x 365 (days) = $286.16 a year to run the 14, 40watt T12 bulbs

Now for the T5's:
220 watts x 14 hrs = 3.08 kWhrs (3080 watts) 0r 30.8 cents a day.
30.8 x 365 (days) = $112.42 a year to run the 4, 55watt T5 HO bulbs.

$286.16 - $112.42 = $173.74 a year in savings.

That's more than the T5 setup cost.

IMHO, if your wanting to light a 55 gal terrarium, 4, T12 are suffeciant as seen in this post, but if you've got somethin bigger for your plants, like Bucky in this post, then I believe the T5's would be a better option than all the T12's needed for good light on such a large grow area.
 
to me, the only real advantage of the T5 compared to the T12 is the amount of wattage that can be squeezed a a given area...

watts is a measurement of energy, 746 watts equals one horsepower, 0.0002928 watt equals one BTU, etc etc etc, a watt is a watt is a watt, regardless of bulb design

so if we have two bulbs that both use 40 watts of electricity and both produce the same amount of usable light then both are equally efficient based upon our criteria

but if one bulb converts more of the original 40watts into heat instead of usable light then its usable efficiency drops, this is why incandescent bulbs typically aren't used to grow plants, too much energy is converted into electromagnetic radiation wavelengths that are of no use to plants, this is why a 20 watt incandescent doesn't put out the same visible light a 20 watt fluorescent does, and yet each is putting out the same amount of energy, just in different wavelengths

but with the T5's being smaller and of higher wattage, you can squeeze more watts into a smaller footprint, here is where the advantage lies

now which puts out more heat... the T5 or the T12, well that i don't know because even though the T5 feels hotter it has less thermal mass being smaller in diameter... so you would have to put bot bulbs in equal sized environments and then measure the delta T...

so at the end of the day would 200 watts of T5 be any more light the 200 watts of T12, probably not ( assuming the same delta t) but would the concentration of that 200 watts be greater with the T5, then yes... but this also assumes the fixture's reflectors both being of equal efficiency... compare a great T12 fixture and an el-cheapo T5 with no reflector and any gains would be lost immediately

according to the law of conservation of energy if you start out with 40 watts then you can only end up with a finite amount of light at 100% efficiency, regardless of bulb design.... but it's how well that energy is converted into a useful form (spectra) and how well the energy is concentrated (watts per foot, reflector design, distance to bulb, PAR, PUR)
that is the true key

but i may be just blowing hot wind too :)

Av
 
T12 lights suck......................more interested in a comparison between T5's and T8's
 
  • #10
OK, let me look at the math. I think it will be a bit more that $13 over 5 years...

You didn't factor in cost of replacement tubes. T5 are more expensive than T12s. Some people replace their tubes every year. Two or three complete set changes in 5 years would seem reasonable.
 
  • #11
I am interested in the difference between T5s and T8s. I am using 6 T12s and 8 T8s.
 
  • #12
the same discussion applies, it is how many watts in how big of space and how efficently are those watts being used... it doesnt matter if its t12, t10, t8, t6, t5 or HID or LED, lights are nothing more then an energy transfer device, converting electrical energy into electromagnetic radiation of various wavelengths... plain and simple, no voodoo to it

if you can cram extra PAR's/PUR's in the same area then light energy levels goes up, it doesnt matter if it is done by moving the lights closer, improving the reflector design or increasing the wattage by using t5's as opposed to t8's or t12's, (but there is a point of dimishing returns.... see photoinhibition)

and FWIW i have great results with t12's, a lot of people do...

more discussion on this same subject

Av
 
  • #13
When someone gets some history with the T-5 lamps, I'll be interested in hearing about their longevity. A few years ago, I invested quite heavily in AH Supply Power Compact fluorescent fixtures (planted aquarium people love them). Building the fixtures was a bit of a pain but I loved the mirror reflectors and the concentrated light output. However, over time, I found that the lamps had a fairly high premature failure rate. The AHS guy was always good about sending replacement lamps but I really hated it when I came home from a long weekend away to find a tank in the dark (and god forbid if I'd run out of spares...).

The failures were always the same - about 1.5" from the end where the cathode(?) got too close to the glass and made a small hole. Otoh, the T-8's were bullet-proof and lasted for years until they eventually burned out or I replaced them for weak light output. The AHS guy said that although I may be experiencing a higher failure rate than some, this was not really unusual.

Since the T-5's are the same diameter tubes as the PC's (I believe), the issue may or may not be the same.... I'm interested in the feedback before I start my next wave of lighting purchases....
 
  • #14
thats about where im at.....have yet to find a better bang for the buck than T8's....
 
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