Light Loss Through Glass (air cooled shade) ??

Hi All, what sort of figure is lost through using an air cooled shade ? i used normal shine shades over the years but have to now use 2 aircooled with glass....

Cheers

um, none...

i always thought/was told it was <10%

frostythesnowthug said:

i always thought/was told it was <10%

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i second that. i was informed 10-15%

thanks, 10% is alot !!!

how much light could you possibly lose through a transparent piece of glass?

about 10 15 percent. ITs like a barrier, the thinner the better id imagine. The light has to 'peirce' through the glass. it acts as a filter in a way.

Its called refraction, and the answer is ALOT depending on glass dimensions..
Bare in mind that a mirror is reflects 40% less light than what ever is hitting it.

The theory of the transmission of light through transparent bodies is derived from a well known law in optics, that the influence of the sun's rays on any surface, both in respect to light and heat, is directly as the sine of the sun's altitude; or, in other words, directly as his perpendicularity to that surface. If the surface is transparent, the number of rays which pass through the substance is governed by the same laws. Thus, if 1000 rays fall perpendicularly upon a surface of the best crown glass, the whole will pass through, except about 40%, which the impurities of even the finest crystal, according to Bouguer, will exclude; but if these rays fall at an incidental angle of 75&#65446;, 299 rays will be reflected. The incidental angle, is that contained between the plane of the falling or impinging ray, and a perpendicular to the surface on which it falls.

Dont panic tho Hedge, the fact that your plants will be able to get ALOT closer to the HPS bulb using a cool tube, will recoup any losses thru refraction

yuuup, damn dude, DAMN. well put.

Que? lol am i that baked

frostythesnowthug said:

Que? lol am i that baked

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ooops.....wrong forum at the wrong time !

Pheweee... i thought my head was fried a lil more than usual.

frostythesnowthug said:

a well known law in optics

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i must be ouside of that loop...LOL

good post

for the exact reason of losing lumens i use no covers over my lights and have 2 occilating fans blowing at the bulbs i can get a 400 hps about 6 inches from my girls without problems if ambient temps are below 78 consistently. for some grows temps are a problem at that point a cover would be good they also have water cooled lights but water is even worse with regards to light penetration.

bicycle racer said:

for the exact reason of losing lumens i use no covers over my lights and have 2 occilating fans blowing at the bulbs i can get a 400 hps about 6 inches from my girls without problems if ambient temps are below 78 consistently. for some grows temps are a problem at that point a cover would be good they also have water cooled lights but water is even worse with regards to light penetration.

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yeah, but i can get my girls under my cooled 400 2 inches from the glass. and the loss of lumens decreases exponentialy the further you get from the source.

well to each his own. in my personal experience i get better growth with uncovered lights but my temps are low. i realize lumen loss is logarythmic(misspelled) especially past 12 inches but i have very good trichrome production at this distence. but again i can only do this because of low temps. when i had reef tanks with metal halides coral growth was much better with no aquarium cover than with and this was at only a few inches. i have seen good grows either way though.

right on. also, i have very few plants so i dont need to cover much area. with it being so close it doesnt cover much area.