LED heat VS HPS heat?

N

nopifarms

Member
Airwalker16 said:
Again, people say watts are watts, but in my mind, it's an 800°F point source of heat 12 hrs a day, VS a 120-180°F point source of heat 12 hrs a day. Lot less heat produced. More so than just the difference in 320 watts less of electricity being used.
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Practically - that was my same logic. But theoretically - the laws of science say otherwise. Guess thats where my confusion really lies. Wish someone could actually test this!
 
Boatguy

Boatguy

Well-Known Member
Airwalker16 said:
Again, people say watts are watts, but in my mind, it's an 800°F point source of heat 12 hrs a day, VS a 120-180°F point source of heat 12 hrs a day. Lot less heat produced. More so than just the difference in 320 watts less of electricity being used.
Click to expand...
Your heat sinks area keeps fixture temps low, but produce the same amount of heat as a small bulb of the same wattage. Energy doesnt disappear
 
Rocket Soul

Rocket Soul

Well-Known Member
Boatguy said:
Your heat sinks area keeps fixture temps low, but produce the same amount of heat as a small bulb of the same wattage. Energy doesnt disappear
Click to expand...
This has been discussed almost to death around here: on the one hand basic thermodynamics says watt in watt out of heat if the thermalsystem remains the same, on the other hand several growers on here have made tests and had hps temps higher than led temps on a watt per watt basis. I think it was nevergoodenough who did this temps experiment in an open space and got higher hps temps than leds watt per watt. However i think cobkits got sorta samey temps between led and HID in a tent.

We havent made this experiment in our grow per se but our openspace will not heat up enough for growing during the winter if we dont dropp a few HIDs in, even with matched wattage.

I am completely with aw16 on this in that there is something more happening here and i believe the hottest point of the light factors into this, and also the size of the space along with cooling method.

To those who were here when diyers did their own heatsink calculations and really did their homework: notice that thermal resistance is a factor of mass, surface area and temprature of the heatsink; the higher the temps get the higher thermal resistance gets as it gets harder to heat the heatsink the higher you go as it gets better at dissipating the heat the hotter it gets. This maybe isnt the smoking gun i would like it to be but its clear that theres more to it than watt in watt out in temps.

This subject is like the worst troll bait ever as there are 2 fairly valid positions:
- Thermodynamics are correct and energy is always conserved but can be transformed.
- HID seems to give higher heat when measured by thermometer.

If i have to go with one or the other i go with point 2 and i feel that anyone who offers up advice on this should do this based on their own measurements and not on what physics says it should be. Thermodynamics are easy in theory but a bit of a nightmare in practice.
 
Airwalker16

Airwalker16

Well-Known Member
Rocket Soul said:
This has been discussed almost to death around here: on the one hand basic thermodynamics says watt in watt out of heat if the thermalsystem remains the same, on the other hand several growers on here have made tests and had hps temps higher than led temps on a watt per watt basis. I think it was nevergoodenough who did this temps experiment in an open space and got higher hps temps than leds watt per watt. However i think cobkits got sorta samey temps between led and HID in a tent.

We havent made this experiment in our grow per se but our openspace will not heat up enough for growing during the winter if we dont dropp a few HIDs in, even with matched wattage.

I am completely with aw16 on this in that there is something more happening here and i believe the hottest point of the light factors into this, and also the size of the space along with cooling method.

To those who were here when diyers did their own heatsink calculations and really did their homework: notice that thermal resistance is a factor of mass, surface area and temprature of the heatsink; the higher the temps get the higher thermal resistance gets as it gets harder to heat the heatsink the higher you go as it gets better at dissipating the heat the hotter it gets. This maybe isnt the smoking gun i would like it to be but its clear that theres more to it than watt in watt out in temps.

This subject is like the worst troll bait ever as there are 2 fairly valid positions:
- Thermodynamics are correct and energy is always conserved but can be transformed.
- HID seems to give higher heat when measured by thermometer.

If i have to go with one or the other i go with point 2 and i feel that anyone who offers up advice on this should do this based on their own measurements and not on what physics says it should be. Thermodynamics are easy in theory but a bit of a nightmare in practice.
Click to expand...
God thank you. Was beginning to feel a bit on the crazy side for a bit. I can't even imagine having a bare bulb 1,000w HPS in my tent. Literally impossible with the small amount of exhaust I need for my LEDs.
 
Airwalker16

Airwalker16

Well-Known Member
@CobKits @nevergoodenuf
Rocket Soul said:
This has been discussed almost to death around here: on the one hand basic thermodynamics says watt in watt out of heat if the thermalsystem remains the same, on the other hand several growers on here have made tests and had hps temps higher than led temps on a watt per watt basis. I think it was nevergoodenough who did this temps experiment in an open space and got higher hps temps than leds watt per watt. However i think cobkits got sorta samey temps between led and HID in a tent.

We havent made this experiment in our grow per se but our openspace will not heat up enough for growing during the winter if we dont dropp a few HIDs in, even with matched wattage.

I am completely with aw16 on this in that there is something more happening here and i believe the hottest point of the light factors into this, and also the size of the space along with cooling method.

To those who were here when diyers did their own heatsink calculations and really did their homework: notice that thermal resistance is a factor of mass, surface area and temprature of the heatsink; the higher the temps get the higher thermal resistance gets as it gets harder to heat the heatsink the higher you go as it gets better at dissipating the heat the hotter it gets. This maybe isnt the smoking gun i would like it to be but its clear that theres more to it than watt in watt out in temps.

This subject is like the worst troll bait ever as there are 2 fairly valid positions:
- Thermodynamics are correct and energy is always conserved but can be transformed.
- HID seems to give higher heat when measured by thermometer.

If i have to go with one or the other i go with point 2 and i feel that anyone who offers up advice on this should do this based on their own measurements and not on what physics says it should be. Thermodynamics are easy in theory but a bit of a nightmare in practice.
Click to expand...
 
T

Turbogrow

Member
Just to add, depending on local climate... I actually have to add a 600hps to my room during winter or my heating is nearly constantly on. Fuck using 2000w for a heater when one 600w HPS almost keeps it off. I just think I'm paying for having that heater on I'd rather use the energy for light. Iv never run a sealed room but you would need hardly any AC using LEDs ever. With decent air exchange it's a struggle to get temps up to 24c in winter.
 
FADING-SILHOUETTE

FADING-SILHOUETTE

Well-Known Member
Led generally run cool enough to touch when in use as a grow light in its intended fixture, HID aka HPS MH MERCURY VAPOR HALOGEN etc all run HOT AS FUCK and once powered up even the tiddly 70w'ers will scorch your finger prints clean off..with that in mind its safe to say led is the cooler temp light to run.

HPS is still awesome to grow with ..the light has an energy that is hard to describe ..but LEDs have pretty much overtaken them now especially with wider spectrums and better (unit dependant) performance and are more efficiant... If noisey fans are a problem for you...go with led ..so so easy to balance perfect growth temps...

I used to love the bigger plants HPS could muster up.. but ive swiched 99% to led withe better results in every aspect all round.

At the end of the day its personal choice.. They both get the job done but LED defo runs cooler - STELTHY :leaf:
 
N

nopifarms

Member
Turbogrow said:
Just to add, depending on local climate... I actually have to add a 600hps to my room during winter or my heating is nearly constantly on. Fuck using 2000w for a heater when one 600w HPS almost keeps it off. I just think I'm paying for having that heater on I'd rather use the energy for light. Iv never run a sealed room but you would need hardly any AC using LEDs ever. With decent air exchange it's a struggle to get temps up to 24c in winter.
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Summers are the biggest concern. especially with 100+ lights
 
FADING-SILHOUETTE

FADING-SILHOUETTE

Well-Known Member
THEFAT said:
I know this sounds weird but i ran a 90w ufo along with some cfls in my cabinet and my temps were up around 83,Now i have since then switched all those lights out for a 250w hps and my temps now run 75..so it all depends how you have it vented
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Its the cfls that increased the temps.. I have loads of CFLs in mine and the temps are high but if i switch the CFLS off and just run my cobs etc temps back right down.. I mean its all subjective ..there are so many variables and factors to take into account outside temps inside temps grow room or tent temps rooms sizes.. Fans how many which ones how many plants etc..what time of year day and night temps.. If you have a cold climate HID may be the right choice ..and in Summer led ...play god. Chose whats right for your grow environment - STELTHY :leaf:
 
Corso312

Corso312

Well-Known Member
Boatguy said:
Watts are watts bud. Leds put out more light per watt, but heat per watt is the same.
Its not radiated the same way, but it is still there
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Airwalker16 said:
Again, people say watts are watts, but in my mind, it's an 800°F point source of heat 12 hrs a day, VS a 120-180°F point source of heat 12 hrs a day. Lot less heat produced. More so than just the difference in 320 watts less of electricity being used.
Click to expand...

Agreed, I've had a 400 Watt hps light in a closet and forgot to open the door before work about 12 years ago.. came home 12 hours later and it was 130 degrees in there, I don't even hit 95 with my 450 Watt LED light in the same size closet with the door closed for 2 or 3 days at a time.
 
Boatguy

Boatguy

Well-Known Member
Airwalker16 said:
God thank you. Was beginning to feel a bit on the crazy side for a bit. I can't even imagine having a bare bulb 1,000w HPS in my tent. Literally impossible with the small amount of exhaust I need for my LEDs.
Click to expand...
Now im feeling a bit on the crazy side. Where does that energy go that isnt light with led's. They arent 100% efficient.
Did you run a 1000w hid in your tent before changing to 1000w of led?
 
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Humple

Humple

Well-Known Member
Boatguy said:
Now im feeling a bit on the crazy side. Where does that energy go that isnt light with led's. They arent 100% efficient.
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I think in many cases it's a matter of dissipation and extraction. HID pounds that heat straight down at your plants, but with LED you have a heatsink spreading that heat and dissipating into the air at the top of the tent/room. If you also run your exhaust at the top, it's far easier for it all to just be dumped outside of the grow space. That's the theory anyway!
 
2cent

2cent

Well-Known Member
My 250watt leds i can run in a 60x60x200 tent at 24c my 250hps runs at 33 in same enviroment.

My 2000 watts of led in 2.4x1.2 runs 27 and i heat it sometimes.
My hps grow 1200 can hit 34degrres so i ise cooltubes and that takes me to 28
 
Airwalker16

Airwalker16

Well-Known Member
Airwalker16 said:
Again, people say watts are watts, but in my mind, it's an 800°F point source of heat 12 hrs a day, VS a 120-180°F point source of heat 12 hrs a day. Lot less heat produced. More so than just the difference in 320 watts less of electricity being used.
Click to expand...
I was way off.... 800°F? Try 5,400°F
 
Rocket Soul

Rocket Soul

Well-Known Member
2cent said:
My 250watt leds i can run in a 60x60x200 tent at 24c my 250hps runs at 33 in same enviroment.

My 2000 watts of led in 2.4x1.2 runs 27 and i heat it sometimes.
My hps grow 1200 can hit 34degrres so i ise cooltubes and that takes me to 28
Click to expand...
This is exactly what im talking about. The thermal system of hps vrs led is not the same so they heat up different. This doesnt mean that thermodynamics have been raped and violated, it just means that in reality things get more complicated.

Also: 1000w led per 4x4???
 
N

nopifarms

Member
Airwalker16 said:
I was way off.... 800°F? Try 5,400°F
Click to expand...
2cent said:
My 250watt leds i can run in a 60x60x200 tent at 24c my 250hps runs at 33 in same enviroment.

My 2000 watts of led in 2.4x1.2 runs 27 and i heat it sometimes.
My hps grow 1200 can hit 34degrres so i ise cooltubes and that takes me to 28
Click to expand...
Wow thanks for sharing. Seems like Watts aren't all just Watts. I guess the question now is - do HPS lights translate well into Watts to BTU calculations? or do LED's?
 
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