ventilation and security questions...

I have 3 questions mainly about ventilation.

1. I am in a area that gets cold so in the colder months should I vent the grow room air into the house and help save on heating or just blow it outside. what about the humidity.

2. Grow room is in lower area of house so I will have to put in some kind of vent in the rear of the house. if i use a dryer vent will that restricted the 6 in. inline fan with the 4 in. dryer vent or do they make larger ones. I also don't want to draw to much attention to the vent, it is about 15-20 feet from the fence/neighbors backyard. Thing room is 1/2 underground and 1/2 over and only vent options I can think of are window that is in front of house (not a option in my opinion) and cutting hole in rear of house.

3. I was going to vent the room through the light hoods out side. The room is 12x5x8 = 480 cf I was going to vent the room with a 6 in. inline fan rated 500 cfm and was going to run it on 50% power to reduce noise. question is should I run the fan constantly or use a controller? I ask because last room i had had a environment controller and when the lights were on the fan was on constantly anyway..

any info would be greatly appreciated... I am building the flower room as I am now just planting germinated seeds.

Heres just my two cents to your questions, hopefully I can help you out alittle bit.
1) If your just venting heat off of your lights (that are closed in) then yes I would just vent the heat into the house during the cold months. But if your set up is like my buddys where its sucking out heat, smell, dust and humidity then no I wouldnt vent it in the house Id vent it to the outdoors.
2) www.htgsupply.com has 4",6" & 8" flexible ducting. I got the 4" 25' for $12. My buddy has an 8" inline fan that runs into a 8" to 6" reducer that hooks into a 6" inline fan that hooks into a 6" to 4" reducer that then hooks into his 25' piece of 4" flex ducting, he hasnt noticed any difference running into a smaller dia. ducting. He runs his to his chimney which is what I advise anyone who asks me where to run it to. All your heat/smell is vented out high above the house to blow away unnoticed by nosy neighbors or the police. I dont advise venting into a wall / crawl space / attic, the reason being all that heat & humidity causes condensation (especially during the cold months) and will make your insulation etc... moldy.
3) Personally I wouldnt vent my room through my lights. Id vent my lights on there own system and the room air through its own. There may be no difference and this is something you may want to look into but, when a friend of mine vent his room air through his lights I remember he had problems like bugs,dust and condensation
(from the Humidity) on the inside of his lights and covers. Id just run it on a timer. Leave it run mainly during your light hrs. then during your dark period have it come on a couple different times to keep the air moving. I would run it at full power for a room your size I would think it would take the full 500cfm to keep your room the right temp. All the inline fans ive came in contact w/ where never really that loud they would just vibrate what ever they were hooked too, but that can be taken care of with bungee cord/ rubber silencers. But if you already have a environment controller Id just use it and let it do its thing.

Nice answer Nate

Thank u for the info. Now I have a few more questions looking at a few different options. If u was to vent through the interior wall to the roof, don't have a chimney. Will 2-3 600 watt lights be enough heat to keep the roof hot before it escapes (no attic just insulated roof) don't want to melt all the snow on the roof that is a sign around here. Next if I do that I have to move my flower room from the walk in closet to the room. But then room is 9x9 and won't be able to vent light hoods separate but air goes out roof vents and no air cleaning needed. But if in closet can vent separate but have to go out side of house at ground level. Not to thrilledabout that and would need to clean air. What would u do Nate or any one? And myast vortex at full speed u could hear the air moving so fast no vibration at all. I don't want it to be heard through the house if possible. Ideas please.