New Grower More Heat From 150 HPS With Internal Ballast or 250 HPS With External?

[yodabuds]

Gadget guy what did you do to take care of the mold problem? I had a bout with white powdery mold (knock on wood haven't seen the ugly bitch in a month ) but the entire grow room is soon coming down and everything redone, walls cleaned , painted with killz, and when grow stuff is down and out of sight going to have someone come in and clean my forced air ducting, than see how difficult it will be to throw one of those uv germicidal lamps into the hvac blower.... Hoping that will remedy things (freaking also had spider mites) so it's been stressful times in Yoda's garden... But knock on wood been able to make it to a few harvests!

 

[cooldm]

Careful ventilating into an attic that has wild temp swings, especially in the winter. If the attic isn't ventilated or you don't vent up through the roof you can have mold issues, ask me how I know lol. Condensation is no fun.....

Oh man that sounds rough. Yeah, the attic has exhaust vents.

 

[late]

If ventilation is an issue, I'd look at CFL or LED.

You can take a 125 watt CFL unit and run a 250 watt bulb in it.
For example, you could veg with a 125 Fluorwing and use
the reddish 250 watt cfl bulb for flower. Or a T5 unit.

Alternatively, you could use an led. More expensive, but your heat problems
go away, and you could get more lumens on the plant because of that.

http://www.amazon.com/Hydrofarm-FLC...65626&sr=8-3&keywords=150+watt+cfl+grow+light

 

[dirty budster]

I appreciate the explanation but there are a couple of things off with this calculation.

First, the 150 watts is just the power drawn by the bulb. The whole unit itself pulls about 200. The specs for the ballast states 1.65 amps at 120V.

Second, the loss in the ballast doesn't necessarily translate to a loss in heat, just lumens. The inductors and capacitors that account for the loss in the ballast will still produce heat.

Well, they're estimates based on the numbers you gave but they should be in the ballpark. The numbers on the bulb could be maximum power under certain conditions. The average power tends to be lower than that. I have a 250W CFL bulb that only draws 218W on average so unless you can measure it it's hard to now the exact number. If it really draws 200W and the bulb uses 150W that would be a pretty poorly designed ballast. Anyway, in the example I gave, you have to consider that the ballast has 172.5W going through it. 150 of those go to the bulb and 22.5W are pure losses that will turn into heat.