Favorite Method: Exhaust From Basement to Attic?

So, my flower and mother/clone/veg room are in a room in my basement. I'm currently ducting the exhaust off my 1000w hps into the main return trunk on the houses HVAC system. That worked fine for 1000w but with the addition of another flower light I'll be overheating the house in all but 20* weather. So, I need a seperate duct circuit to get any additional heat up into my attic where it will dissipate naturally. Obviously, I'm aware that carbon filtering will be required. I'm already familiar with this aspect.

So, aside from the "where to hide the 6" duct" issue how about head loss per foot of duct? I know, at a minimum to get the peak of my attic I'll need 19+ feet of ducting from the point that it exits my room. I'm just looking for a rule of thumb basically. Similar to how we know that flow will be reduced by ~50% for every 90* elbow. So, 1' of 6" duct = x% flow loss? Also, how much do duct mufflers cut flow? Don't want the neighbors hearing the jet from the attic if I'm going to need 1000+CFM.

I like the heat into the return line idea. Pretty slick!

Your going to vent outside the house though right? Humidity could cause problems in your attic. Plus you would need a vent anyways or no air will flow.

Anywho, the friction loss rates are found here: http://www.engineeringtoolbox.com/duct-friction-pressure-loss-d_444.html

link around at that site, very good info. If you have a big run, i would consider an 8" run. Or a big custom built muffler and a discreet outlet some where in the side of the house as opposed to the attic.
Cheers.

Thanks for the link. You make a good point about the 8" being a good idea. But that makes this problem more complex. Where in my house do I run an 8"x8' tube through the first floor and then conceal it?

About the venting through the roof idea. I'm absolutely not cutting a hole in the shingles. So, I'd need to either come through the gable or rely on the natural air movement from the soffit through the ridge vent. Anybody just plain dump into their attic and let the design do its duty? Note: My house is 3 years old so the attic is very up to code as far as venting requirement.

I'm beginning to think going water cooled with CO2 is a better idea. Its much simpler to get water where you want it vs air.

well what i would do is run it through a closet some where through the first floor, and depending on the size of attic, itll just dissipate the heat and maybe raise the ambient temp up there oh, 5-10 degrees.

One person I knew had PCV stack pipes for his toilets. The stack pipes, as all of them do, went through the roof. He cut into one and installed a 'Y' so he could vent out his stack pipe. Another friend put a 'Y' into his dryer vent that went outside. Septic gas is warm and dryer exhaust is warm and what difference in temperature there might have been evidently has never raised a red flag. With a carbon filter there was no additional odor in either situation.

I am not saying they are perfect options, but I do know people who have gone with them.

If your attic has a ridge vent and you can run an exhaust line up into your attic you can run it along just below the ridge, the full length of the right vent. You plug the end of the line and put holes along the line running just under the ridge vent so the warm air is spread out along the entire ridge vent and rises and exits.

If you have some other form of roof vents you could possibly run a line to them and exhaust through them.

Whatever you do you want your exhausted air to be able to exit your attic as quickly as possible. It will be moist and a moisture buildup could cause problems over time.

OK spring is here and I can tell its getting close to needing to switch this system up for better efficiency. I have not used the furnace at all in a month and outside temps have been 25-45 degrees. I've been running the vent fan above my stove continuously for a while now on low setting to be sure to keep stray odors as well as smoking odors under control. I figure in the summer to keep doing that is very inefficient since that air is not from the source of the heat in the house. So, I'm going to go through with this plan as follows.

I'm adding another 1000w dimmable Lumatek light to replace all the random BS CFL's I've been using as "supplemental lighting". All these extra twisties have added nearly 400w, as well as a fuckton clutter to the room while minimally increasing yeild. So I'm ditching those for use elsewhere in the house in favor of a true flowering light. The 2 1000 watters will be running on the same venting system. The room is a bit large for even 2 1000 watters so the ambient temp should be controllable with 6" ducting. All of the intake into the room will be passive. The air in the basement is naturally very cool in the summer so this should work well. Also, through the winter I've removed every scrap of carpet and padding to allow the concrete/earth to help with the cooling. The difference in ambient has been staggering as I remove carpet. The 2 lights are in Magnum XXL 6" hoods. The ducting will run out of the room up through the master bedroom closet and into the attic. Once in the attic they will go into a suspended and potentially throttled back Dayton 800CFM squirrel cage blower and then be distributed to the top of the attic where there is a full length ridge vent. The house is 4 years old and as such very up to to code. All the soffits are vented as well. The attic is in places 14' high and 90'+ long plus a garage section. So I'm not concerned very much about temp issues; the ceiling of the first floor has R24 worth of blown in insulation in places so even 100degree temp in the attic hardly effects the house. Humidity I am concerned about though. I'll be monitoring this closely. If its regularly above 65% or see any indication of mold I'll begin thinking about a solar powered vent fan. I've found these for ~$350.

If the Dayton blower doesn't have enough power I will be installing the 6" inline 440CFM fan just after the carbon filter but before the hoods as a booster. This is where I'm not sure any benifits could be had. Is the limitation of a long duct run unable to be overcome even with a "booster" fan? First hand experience would be greatly appreciated with this issue.