# All That Air! A Guide to Proper Ventilation



## ExDex1x1 (Feb 6, 2011)

*This guide is a work in progress. If you have any information you feel would help improve this guide feel free to send me a message or post below (Sending me a message probably best in case this thread grows to ridiculous lengths, I'll probably stop digging through it at some point.) and I'll be sure to update the post as soon as I can (and of course give my contributors credit!). Enjoy the read and happy growing!*


So I've seen about a million "What kind of fan do I need to cool this light" "What kind of fan do I need to vent this tent properly" threads here, and I'm sure there's a guide on the forums somewhere, but it hasn't been stickied and it definitely isn't being read by majority of the members on this forum. I'm doing this guide on a whim, so I apologize if the organization is a little wacky or if I miss something. Just let me know if there's anything you'd like to see added and I'll pop it in this post.

*This guide is assuming you do not have CO2 tanks running in a sealed tent environment, this is an open air constant flow room where air is constantly being exchanged to replenish your air and CO2 supply naturally without CO2 generators or tanks. If you are using CO2 this is not the method to use, you'll be wasting your money pumping all that CO2 out of your tent the second it's pumped in. Do not do this.*
Terms used: 
-Passive Exhaust/intake: Removing/adding air from your room without the assistance of an exhaust fan.
-Active Exhaust/intake: Removing/adding air from your room with an exhaust fan
-CFM: Cubic Feet Per Minute (of air) this refers to the amount of air moved by a given fan. For instance a 500CFM fan will move 500 cubic feet per minute of air.
-Negative Pressure: The air pressure outside of your growing space is greater than the air pressure in your tent, this causes air to passively enter your room through any entry point the air can find.
-Positive Pressure: The air pressure in your room is greater than the external, causing air from inside of your tent to evacuate the room through any point the air can find to flow through.


-----------------------------Part One: Ventilation Basics-------------------------------------------------------------




Now everyone knows that proper airflow is key to a successful grow for many reasons, having adequate ventilation is necessary to manage air temps, preventing a large number of bug and some mold and mildew infestations, and of course, providing fresh air with good ol CO2 for your hungry ladies.

For the sake of simple mathematics, the example room I will be using for this guide is a basic 10x10x10 grow area. All of the math done in this guide is easily applicable to your space, just replace these dimensions with the dimensions of your room.

So lets say you're growing in this 10x10x10 environment. The first thing you need to know is how much air you need to bring into this space to properly ventilate. The base amount of circulation needed is debatable, I've seen guides that say you need to replace the air in your room every 5 minutes, some say every 2, others say every minute, and I'm sure there are others. For me, I prefer to exchange the air in a room at LEAST every 2 minutes. 

Before we jump into the math, I'd like to cover the basics of air exchange. Negative pressure is your best friend. It is far more efficient to _remove_ air from your room than it is to try and _force air in_ to your room. Here's why: When you try to refresh your air by forcing air in, and attempting to use a passive exhaust, you create positive air pressure within your tent. This means that you may be exhausting air at a decent rate, but more often than not it is at a rate lower than what is specified on your fan. A 500CFM fan used as a forced intake, without adequate exhaust, for instance, will actually be pushing significantly less air than 500CFM.
If your passive exhaust is smaller, or even equivalent in size to your intake, the air will not be forced out at a rate equal to the intake, causing positive pressure in your room. Your fan will be attempting to force air in which is at lower pressure than that in your tent, meaning that less air will actually be pulled in than the rated 500 because the lower pressure allows air molecules to spread further out, so each rotation of your fan blade is moving less air than it would if your external air pressure were higher than internal air pressure.


---------------------------Part Two: CFM Calculations--------------------------------------------------------


Now onto the math:

Assuming a 10x10x10 area, we need to calculate how many cubit feet of air are in our room, this is a very simple process, simply multiply the dimensions of your room. 
10x10x10=1000cuft. So to exchange the air in this room every 2 minutes, we would need at the minimum a 500CFM fan. This is not to say that a 500CFM fan will maintain temperatures in your tent at a nominal level, it IS to say that every 2 minutes, you will have exchanged the entire air content of your room for new air pulled from the exterior of your tent. Many people confuse the optimal air exchange rate with optimal temperature control, these are two very different animals.

If you want to get a little more technical, and save a couple more bucks on your fans, you can also calculate the amount of space taken up by your substrate and other items in the room.

Lets assume again, that we are in the same 10x10x10 room with 1000cuft of air when empty. We're now going to add in two sets of flood tables for our grow. Most of you like to maximize space, and I like to use round numbers for my examples, so lets say you have 2 equal size tables both measuring 3w x 8d x 2h (assuming you aren't putting your tables on the cold ass floor!), our area taken up by tables would be (3x8x2)2=96 cubic feet of space. Now we take 1000-96 and get 904/2 (assuming 2 minute air exchange rate again) and we end up requiring a 452CFM fan. Now a lot of you are thinking, wow that was pointless this fan is barely smaller than the original, but keep in mind that a difference of ~50 CFM can also be a difference of $25 or more, and will of course, be quieter, and use less energy provided you are buying two fans of the same type.


------------------------------Part Three: Intakes-------------------------------------------


Now that we've found a fan that is going to properly exchange the air in our room, we need to cover the next topic of airflow: intakes. 

Assuming you're using the optimal fan for your room to exchange air every 1-2 minutes, air intake is very very simple: Passive intakes. The negative pressure generated by your exhaust will cause the air outside of your tent to have a natural tendency to disperse into your tent in order to achieve equilibrium. Air is naturally seeking to balance pressure by moving air from high pressure areas to areas of low pressure. Think of this as being in a 10x10 room with 25 people. If you have 25 people all crammed into one corner of this room, you're all going to be miserable and bunched up against each other, naturally you'll want to spread out so you can make yourself comfortable. This means, that we don't need a second fan to pull air in, mother nature will do the work of the fan for us. All you have to do is have an opening in your tent to allow the air to flow in. It's advisable to put either a carbon filter or a HEPA filter (like the ones on your home's airconditioner/furnace.) This will keep any unwanted dust, mold, pollens, and other nasty particulates that you don't want getting to your plants, and make your environment much more stable. The question is: How large should this intake hole be? The answer is simple: You want the intake to be approximately the same size as your exhaust, OR what ever size fits your HEPA/carbon filter. You don't want to have a 10"x10" HEPA filter covering a 3"x3" intake, you'll be wasting surface area on the filter and replacing them much more frequently. 

Now that we have our intake and exhaust covered, we need to talk about air circulation inside the room itself. This is generally achieved by the use of oscillating fans. Now you're probably wondering, why, after all that effort in our exhaust/intake system, do we need MORE air movement? The answer is simple. 500CFM is sufficient to exchange your air, but not to MOVE it within the tent. You want your plants to have air constantly flowing over as much surface area as possible. This will discourage the growth of mold, and prevent pesky critters from landing and making a home for themselves on your plants. This is something we don't want for our ladies after all the work we've put into them. Now how much air circulation is enough? This is really easy to gauge. Standard oscillating fans will have anywhere from a 30 to a 90 degree coverage area. You want to add a fan to your room, turn it on, and stand in various locations in your room. If you can't feel a fairly strong breeze coming off of the fan at any location in your room, the inner branches of your plants certainly won't feel it either. Continue adding more fans until you are confident that there is no location in your room (at least where plants are growing, your chair in the corner doesn't need proper air circulation, it'll be just fine.) then you are done adding fans.


---------------------------------Part Four: Exhausts and Stench Control------------------------------------


Now I'm sure a bunch of you saw the exhaust section and immediately were screaming to yourselves "WHAT THE HELL HE DIDNT TALK ABOUT CARBON FILTERS OR OZONE!?!?!?!" 

Well, that was for good reason, as exhaust systems are one of the marijuana grower's worst nightmare more often than not, so I decided to have a larger section for them. Everyone is scared that their neighbors will smell something and alert the 5-0 or that the heat from their exhaust is going to be caught on the growers natural enemy: The FLIR. 

For those of you who don't know, FLIR stands for Forward Looking Infrared Radar. What this is, is a police tool that shows differences in temperatures, with a *claimed* accuracy of within 1 degree F. This is bad news for everyone, right? We're all totally screwed. Wrong. 

FLIR is pretty intimidating technology, but it is SO EASY to defeat. FLIR cannot see through your walls, FLIR cannot see underground, FLIR cant see a lot of things. The easiest way to defeat a FLIR is to place your grow room in a central location in your home. If the heat from your grow room is not touching an outside wall of your home, it is undetectable to FLIR, by the time the heat spreads through all of your home, it will appear to be the normal air temperature of your home. The other way to defeat FLIR is with some creative insulating and duct work. 

Insulating your room: If you are growing in an attic, or along an exterior wall of your home (unless you're using LEDs or only a few tiny CFLs), you're going to be giving off a pretty distinct heat signature. The simplest way to prevent this, is to create an air buffer between your grow room and your walls. You want to have space between your tent or DIY grow room and the exterior walls of your home, the more space between the hot air in your tent and the external walls of your home, the more it will dissipate and the less obvious your heat signature will be. 

If you're growing in an attic, more often than not your insulation is going to be a crap shoot. At best you might have R-13 standard fiberglass insulation, this does a great job of keeping a little bit of heat out and a little bit of your homes air (cold or hot depending on if your a/c or heat is running) in. Note that growing in an attic is very ill advised. Year round this is going to be the warmest room in your house. Heat from your home during the winter will naturally rise, it ends up in the attic. During the summer, most attics have no vents in them, they're generally much warmer than the rest of your home from lack of air flow, and from being in such close proximity to the exterior temperatures. If you have the option, don't grow here. If you absolutely are dead set on your attic, insulate your room thoroughly. I'd recommend some top quality foil insulation. It reflects heat inwards and dissipates some of the heat that touches it through multiple layers of insulation, and all you have to do is tack it up to your walls /ceiling with a staple gun or nails. Here's an example of the insulation I'm talking about.

Now for the all important topic: Carbon filters on your exhaust.
For those of you don't know, carbon filters are a relatively low cost (in comparison with other methods) of removing odors from the exhausted air leaving your room, so your pesky neighbors don't notify the police about the skunky smell coming from your home. 

Now there are many sizes of carbon filters on the market, DIY methods, and all sorts of price ranges. The general rule of thumb is the higher CFM fan you are using to exhaust (and the more cubic feet of space in your room) the larger carbon filter you will need. Carbon works by surface area contact with the air removed from your room, the higher the CFM of your exhaust fan, the less time the air will be spending in your carbon filter, which in turn means you will need a longer carbon filter in order to allow the air to have ample time to get rid of that stanky dank smell. This is kind of a gray area for me, I really don't know what to recommend as a baseline unfortunately since I haven't had experience with enough different size carbon filters to give you a scientific explanation of how large a filter you need. The one thing I will tell you is that if you are venting directly from your exhaust to the outside air, it's ALWAYS better to air on the side of caution. Its always better to have too big of a carbon filter than it is to have the pungent aroma of marijuana spewing from your home. For this reason, I'd recommend buying your carbon filter locally if possible. This way you can take it home, set it up, see if it works, and if it doesnt go exchange that thing asap! 


---------------------------------Part Five: Light Traps----------------------------------------


Light traps. Light traps are a very simple concept for preventing light leaks while allowing adequate air flow. For those of you using tents with open passive vents or any passive intake for that matter, these are hugely helpful. 

A light trap is very simple and can be made from any number of materials. The basic concept is to block rays of light from entering your room during dark hours while still allowing air in. 

A very basic diagram for you here, this can be constructed out of any material from cardboard shoeboxes to lumber to metal, what ever you have will pretty much work. 
__ __ <--- assume this is your tent's wall and vent opening.
|----- |
| -----| <---this is the structure you want to build. By staggering inserts inside your box, you assure that light will not be able to enter, while air will flow freely around the dividers. The more dividers you add the 
|----- | better protected your box will be from light leaks, generally 3-4 will do the trick. The idea is to keep the dividers very close together. If you spread them out too far, light rays will be able to bend around the dividers and enter your tent, also make sure your dividers have a decent amount of overlay. If you have short dividers, you're not doing anything productive here.

You can also make light traps by using 90degree ducting. By attaching 90s to each other you can block any light. It's recommended to use several 90s and create at least 1 180 degree bend in your trap to make sure you have no leaks. A single 90 will not do the job, anything over 180 should be fine, attaching a 90 to the end of our 180 (facing the opposite direction so you don't run your duct back onto itself and block significant amounts of airflow) is recommended.


-------------------------------------------CO2 Sealed Tent and Timed Exhaust Guide(In progress)-------------------------------------------------------------------------------------


CO2 is one of the best ways to help expedite plant growth and improve your ladies' ability to perform photosynthesis. Carbon Dioxide is one of the main proponents of photosynthesis which helps your plants create basic sugars and form new cell structures. Increasing the levels of CO2 in your garden can help improve your yields vastly and help create denser, more closely clustered bud formations. This portion of the guide will explain the different methods of implementing CO2 in your garden, as well as the different ways of providing CO2 for your plants.

First, you'll need to decide what method of garden you want to be using. There are several ways to use CO2 in your garden, here are the most popular.

----Sealed Room----
The sealed room is fairly straight forward, we skip the previously mentioned intakes and exhausts, and in their place we use air conditioners, humidifiers, dehumidifiers, and carbon filters within our tent to control the environment. Since we won't have an exhaust to remove stale, hot air from our room, we need to bring in an air conditioner. You can find portable ac units at most of your local home improvement and hardware stores, and in some cases your local hydro shop or garden center. The size of the air conditioner you purchase is going to be largely dependent on the space of the room you are growing in. Each AC unit should have manufacturer's recommendations as to how many square feet of space the unit is capable of cooling, keep in mind that most manufacturers assume that you'll be using this unit to bring your room to standard room temperature of around 70-72 degrees, so it's okay to purchase a unit that is slightly below your actual square footage, since we won't be going quite that low in temp. The other thing you'll need to consider is either a humidifier or dehumidifier depending on conditions in your room. If you are using a hydroponic setup, most likely you will need a dehumidifier to compensate for an increased amount of water and nutrient solution evaporating due to slightly higher than normal temperatures that are allowed when using CO2 in a sealed room environment. You'll also need to have a carbon filter, preferably hooked up to your light's cool tube if you're using one (highly recommended in sealed rooms.). The carbon filter will be used to 'scrub' the air in the room of any impurities and other unwanted particulate that may be floating in the air such as dust, dander, or god forbid, pollen. 

----Timed Exhaust System----
Using a timed exhaust system is a compromise between the standard air circulation described in the first portion of the guide, and a sealed tent configuration. This method requires quite a bit of guess and testing and a little bit of sweat equity when you've first put it into the works. Instead of having your exhaust and intakes open at all times of the day, you will instead have your intakes and exhaust sealed, and pump the room full of CO2 for a few hours (while your lights are on). When temperatures in your room reach a certain threshold, or when your lights are going to be turned off (most likely temperatures will be the determining factor here.) your exhaust and intake will be turned on, cooling the room, and replacing the air within your room. Keep in mind this tends to get quite a bit more costly than a sealed tent environment since you're constantly purging and refilling your room of CO2. The aim with this style of CO2 delivery is to have your room filled with CO2 during the light hours for as long as possible before temperatures become unmanageable. This means that within your room you'll more than likely want either an excess amount of circulating fans, or an adequate AC unit. You want to have at least 2-3 hours of CO2 saturation before you have to vent the room, ideally, you would want your entire light cycle to be with the room filled with CO2. 

----Sealed Tent, Vented Cool Tube----
This is another option available to some growers depending on the layout of your room, this may be an excellent option to use. This setup follows the same guidelines as a standard sealed tent, with one key difference: a carbon filter outside of your room is attached by sealed duct to your cool tube on your lighting fixture, and exhausted out of your tent. This will make temperatures much more manageable within your room while making sure that you aren't pissing away money by pumping CO2 out of your room every few hours. This is an excellent solution for those who are looking to run multiple high wattage fixtures, but don't necessarily have the money to spend on a top of the line AC unit. The only major disadvantage to this method is that you'll require a carbon filter (or hepa filter) for your cooltube, and a 2nd carbon filter to recirculate and 'scrub' air within your tent.


----------Delivery Methods-----------
Now that we've covered the basics of how you'll need to modify your grow room to properly use CO2, let's cover the basic ways of how to generate CO2 levels within your growing environment!
First things first though, we'll need to be able to measure the amount of CO2 within the room. Much like your nutrient solutions, this will be measured in ppm (parts per million), a great place to look for meters online is here.

Now that you've got a meter, it's time to choose a delivery system. The only system (that I know of) that I won't be covering, is the ghetto-rigged yeast sugar and warm water method, since that's useful for basically...no one... If yeast sugar and water are your preferred method for CO2, you probably aren't growing in that large of a space, and CO2 isn't really that large of a factor at this level (not to mention that you could just buy a CO2 tank and have it last for a year instead of spending all your money on baking supplies).

Tanks. Most people tend to go with the tried and true method of getting CO2 directly from a tank, these can be purchased at your local welding supply store, and with a little research you can probably locate a local vendor. When buying a tank, it's key to get a regulator. This will keep the CO2 releasing from the tank at a predetermined level, and will keep you from either wasting money and releasing too much directly from the tanks valve, or under saturating your room by not releasing enough. It basically takes the guess work out of the equation, and makes things much more manageable and controllable. *Warning* Please keep your tanks away from excessive heat and be careful not to drop them. This is a pressurized gas and if you happen to knock the valve off of the top of the tank, you're looking at a 25 pound rocket that can put a decent sized hole in a wall...or your chest.* The obvious down side to this method is that you'll be making pretty frequent runs to refill your tanks, and it can be a pain in the ass depending on how far you live from your distributor. This method is recommended for small to medium size gardens, and for those of you who live very close to distributors and don't mind lugging around tanks everywhere. 

CO2 Generators. 
CO2 generators work by burning either propane or natural gas, the biggest advantage to these bad boys is that you can connect them straight to your home's gas or natural gas line (make sure your unit is compatible with natural gas if you are planning on using natural gas. Some units may be only compatible with one or the other, and it's best not to ignore manufacturer's instructions when you're fucking around with highly flammable gas.) The downside, is, as usual, the increased initial investment in the unit. These are recommended for medium, to large scale growing operations and warehouse situations. 

----------------------Proper Implementation of CO2 within Your Garden-----------------------
Much like your nutrient solution, plants will be able to use only so much CO2 at each stage of growth, excess will not damage your plants, but it also won't help, and this stuff gets expensive!

From seedling through the first 2 weeks of growth you want to keep CO2 levels at approximately 450-650ppm. Normal air can have anywhere from 200-500ppm of CO2 on its own, but in sealed room environments plants can quickly diminish this concentration to 0-100ppm in a matter of hours or even minutes depending on how many plants you have in your garden. Plants are just beginning to grow and will not yet have the surface area to be absorbing a full concentration of CO2.

From 2 weeks on through most of your vegetative growth, you want to keep CO2 levels anywhere from 850-1000ppm. Plants will begin to grow very quickly. Since you're using CO2, you can also run your temperatures slightly higher than normal, and humidity levels should also be run slightly high. Plants kept in high humidity (50-65% depending on strain) will not have to replace water that is being lost through leaves as often if they're receiving ample water from the air around them. This will allow the plant to focus on new growth, rather than maintaining old growth. Temperatures should be kept around 85F during light periods, and 80F during darkness. The low difference between light and dark temperatures will promote tight-knit branching patterns, which will allow you to have maximum yields within a smaller amount of space. Plants will grow more bushy rather than spread out and lanky. If you plan on releasing any predatory insects to prevent spidermites and the like, it is best to do so during your 3rd-4th week of vegetation, while plants are still relatively small. You'll end up needing to release fewer predators than if you wait until you have large plants. 

For the last 2 weeks of your vegging, you want to increase your CO2 to around 1200ppm, lower temperatures to 80F/75F for light/dark respectively. Humidity should also be lowered to around 40-55% depending on strain.

During flowering, you want to maintain relatively low humidity (40-55% depending on strain). Maintain previous indicated temps of 80F/75F. Maintain CO2 at around 1500ppm.

When your plants are around 4-6 weeks from finishing flowering, you want to really pump up the CO2. Anywhere from 1600-1850ppm is acceptable, anything above 1850 is most likely going to be waste. Your plants should really begin to show significant resinous growth at this point.

2 weeks before you harvest (about the same time you cut nutrients for hydro users) return CO2 levels to around 400-650ppm. This will prevent your buds from tasting like a piece of gum that got stuck to your shoe and carried around on your heel for a week. Plants will use up majority of the excess CO2 within their leaves, and at this point 650ppm will be more than sufficient for the plants to continue growing without sacrificing bud flavor and smoothness.

As usual, 48-72 hours of darkness with no supplemental nutrients or CO2 is recommended prior to harvest. 



-------------------------------------------Cool Tubes and You-_Coming Soon!_--------------------------------------------------------------------------------------------------------------------------------------

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-------------------------------Updates and Revisions---------------------------------------
02/09/11-Spaced out sections a little more to get rid of some of the wall o' text feel. Added additional information into CFM calculations sections to go a little more in-depth and provide clearer explanation. Will be adding some pictures later this week for those of you who prefer pop-up books to the newspaper. Removed the 'other' info and placed in the post below so people who don't give a crap about the other info can know where to stop reading  Added basic CO2 users guide, more detail to come when my brain is less fried.


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## ExDex1x1 (Feb 6, 2011)

------------------------------------Other Related Information and Tips You Should Know!--------------------------------------------------------------------------------------------------------------------------

Now as a bonus, Creative ways to vent that air that a FLIR won't detect, and other smell related tips! 

You'll recall FLIRs detect differences in air temperatures on surfaces and of moving air, this means that 80 something degree air blasting out of your mailbox is going to raise some eyebrows. 

There are several ways to defeat the FLIR again, most of them are fairly straight forward.
1. Venting into your home. Very simple, just exhaust your hot air into a room central in your home (Not in the same room as your grow room, you don't want your intake to be sucking up nasty hot recycled air.) and allow it to dissipate before reaching the outside. For most people, this isn't realistic because your AC is going to be running like crazy to keep up with the heat and you're going to be sweating your ass off any time your lights flick on. 

2. Venting through your chimney. This is ill advised in the summer. If its winter time, go nuts, your chimney will be spewing hot air anyways, but heat coming from the chimney in the summer is, again, going to raise some eyebrows.

3. My personal favorite, and the best way to go. Your dryer vent. Almost everyone has a washer and dryer (unless you're in an apartment, which you shouldn't be growing any ways because you're putting yourself at huge risk if your land lord ever has to barge in if/when something goes wrong in the unit below, above you, or in your unit.) and every dryer has a 4"-6" vent. When you're going laundry it's constantly blasting out hot air, and the best part is, it's not suspicious during the winter, and a FLIR scan will NEVER ever sit around long enough to determine that its suspicious. (Meaning they're not going to sit around long enough to notice how strange it is that you've been doing laundry for 18 hours straight.) A simple Y duct can be used to tie into your dryers exhaust vent and the best part is that even when your dryer isn't running, there's residue and lint and all sorts of shit already in that vent that will help mask the smell of marijuana even more.

Things to NOT do: Do not vent into your public sewers or floor drains, or out windows, doors, or other areas of your home. Venting into the sewer may not get you caught because of the smell, but pumping air down can create some funky pressure situations and if your exhaust fan fails you might just end up with your neighbors recycled lunch shooting up into your home, there's also a chance that a city/state employee will be doing standard maintenance and realize that there's air flow coming from somewhere that it shouldn't be, and launch an investigation to make sure that there isn't something seriously wrong with the sewers, which may lead them back to your home. Venting out of doors windows or what ever other crap you can think of on your home is a bad idea, heat coming from locations it shouldn't be coming from is just not good.

Some people will also be tempted to tie into their oven's hood exhaust if you have one, this is also a bad idea since FLIR is so accurate. There's a large difference between the heat signature that's emitted from a grow room and the heat that's pumping off of your 350-400something degree oven. Don't do it.


Now some other random tips for if you're paranoid or you think your carbon filter isn't quite cutting it and other tips:

Lavender and other pungent smelling plants can be a growers greatest asset, plant anything that you can around your home, use pungent smelling mulch and fertilizers outside to mask any smell. Your neighbors will just think you're maintaining your home and they'll more than likely be grateful to your for raising their property value! 

Never tell anyone about your growing operation, no matter how legal it may be. Majority of growing operations aren't stopped by FLIRs or other police work, they're shut down because some moron ran their mouth in the presence of the wrong person. Remember that every single person that is aware you're growing is just another liability for your livelihood. 

Pay your damn bills on time! People often worry about being flagged by electric companies, the fact is that this rarely happens. Electric companies are out to make a buck, they're not Mr. GoodyTwoShoes and all morally opposed to marijuana. They ARE however, opposed to large electric bills that aren't being paid on time. Never give them a reason to investigate you, always pay on time. A general rule of thumb for electric usage within normal levels is that for every room in your home you can safely add 1000w to your usage. For every person living in your home you can add an additional 250w comfortably. For a 5 room home with 4 residents, 5000w of lighting is just going to show up as billy leaving his god damn xbox on all night or dad watching the NCIS marathon on his bigscreen, or some nerdass playing World of Warcraft for 3 weeks straight on his 1000w gaming pc.

Another great way to gauge your electric bill is to casually chat with your neighbors. Pretend to have sticker shock over your last bill and try and draw out an answer from your neighbor. As long as you're not running 3x his bill in an equivalent home with a similar number of occupants, you're golden.

Get a home surge supressor. These can save you 10-40% on your electric bill monthly depending on how high quality of a unit you find. Contact a local electrician and ask for their opinion on what works. My uncle installed ours, and the item number yielded no information on google, its just a black box with a red light on it, but I know it cut my energy costs by about 23% average per month. 

Make sure your home is properly insulated, buy high quality windows, check your home for foundation cracks, ect. Maintaining your home is one of the best ways to save on electricity. Shitty windows can let air escape from your home which means you're running the A/C or heat more and more running up your costs significantly. Cracks in your foundation will do the same, as will improper insulation.


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## flamdrags420 (Feb 6, 2011)

Very Good Post. A little off topic towards the end though. This should be a sticky as there is none for venting and air movement.


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## ExDex1x1 (Feb 6, 2011)

flamdrags420 said:


> Very Good Post. A little off topic towards the end though. This should be a sticky as there is none for venting and air movement.


 Yeah i kinda got to rambling but I haven't really seen any posts about keeping your home up to par and its semi-related to ventilation so I figured I'd toss it in there as a bonus.


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## flamdrags420 (Feb 6, 2011)

ExDex1x1 said:


> Yeah i kinda got to rambling but I haven't really seen any posts about keeping your home up to par and its semi-related to ventilation so I figured I'd toss it in there as a bonus.


not a problem at all. I'm the same way. =)


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## ExDex1x1 (Feb 6, 2011)

Also want to try and work humidity and temperature control into this but those are much more situational, and it's also really hard to put any math or facts to back up how many fans you would need to maintain a certain temperature, there's just way too many variables to calculate. If anyone has some ideas on how to properly do this I'm all ears.


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## ExDex1x1 (Feb 7, 2011)

Bumping since I've already seen a bunch of posts that were covered in this guide today! Help clear up this forum a bit more.


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## Whatamidoing21 (Feb 8, 2011)

That is a nice read, even good enough for people who are using CO2 to learn the basics. Are you planning on doing one with CO2? I will be really interested in that.


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## flamdrags420 (Feb 8, 2011)

Al's faq thread over in the hydro boards has a nice bit of fan info that you could ref for details and pics of the fan types to add to this catalog


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## ExDex1x1 (Feb 8, 2011)

Whatamidoing21 said:


> That is a nice read, even good enough for people who are using CO2 to learn the basics. Are you planning on doing one with CO2? I will be really interested in that.


Yes, I'm planning on updating this with some information for CO2 users also, I'm doing a bit more research on the topic to make sure I don't spread any misinformation, there's plenty of that on the internet already! 

I'll also look into that FAQ and put in some more details sometime this week. Been a bit busy at work so I haven't had much time to work on this guide yet, hopefully by this weekend I'll have some more updates!

Edit: Just realized that FAQ is 182 pages long...that's gonna take awhile haha. I'll delve into that saturday or sunday when I have a few hours to dedicate to scavenging through there. I've been having a bit of trouble finding some good articles to pull information from for CO2 as well, the extent of my knowledge on CO2 is pretty much that plants love it around 1500ppm I pretty much just did what most people do and bought a regulator hooked up to a tank and let loose, but I'd really like to find some articles related to cannabis and better explain the benefits, once I've found some good sources I'll start pecking away!


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## mrmadcow (Feb 9, 2011)

bump & my vote to stickie it


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## ExDex1x1 (Feb 9, 2011)

mrmadcow said:


> bump & my vote to stickie it


 Thanks for the support! I just finished typing up a huge addition to the guide for CO2 growing...and my computer crashed. Far too frustrated to redo at this moment, and I have to head off to work. I'll try and get around to it later tonight, and I'll be bumming around looking for some good example pictures to put up with the guide some time this week, as well as a section on cool tubes


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## beeznutz (Feb 9, 2011)

really, really, good info- big ups to you 
and def keep it coming, especially pix&diagrams for over all design but personally i'm
interested in ways to built the passive vents without letting light in....


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## Whatamidoing21 (Feb 9, 2011)

Looking forward to that CO2 part. My biggest question is if it is absolutely necessary to have airflow in the room. My idea on the whole thing, because I am really sold on CO2, is that when the lights are on I will have all the air moving in and out of the room stopped. There will be a dehumidifier and A/C and the lights will be cooled with a cool tube to take care of the air situation, Then when the lights turn off, start moving air through the room. This will essentially keep the room at 1500ppm at all times during the light cycle.


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## ExDex1x1 (Feb 9, 2011)

Whatamidoing21 said:


> Looking forward to that CO2 part. My biggest question is if it is absolutely necessary to have airflow in the room. My idea on the whole thing, because I am really sold on CO2, is that when the lights are on I will have all the air moving in and out of the room stopped. There will be a dehumidifier and A/C and the lights will be cooled with a cool tube to take care of the air situation, Then when the lights turn off, start moving air through the room. This will essentially keep the room at 1500ppm at all times during the light cycle.


Yea this is what I was working on typing up earlier. I just got home from work so after a quick meal and a couple bong rips I'll be retyping that portion of the guide.


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## ExDex1x1 (Feb 9, 2011)

Updated CO2 section, it's a lot less in depth than what I had typed up this morning, but I kinda forgot most of what I was talking about this morning so yeah. Gonna add some information about environmental controllers and such later this week. Let me know if there's anything else you guys would like to see covered in this guide.


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## mystifiedbongs (Feb 15, 2011)

great advise, i really learned alot in a short amount of time, really appreciate it


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## matatan (Feb 16, 2011)

good stuff plus rep. should def be stickied


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## budleydoright (Feb 16, 2011)

i run my co2 at 1200-1500ppm from seedling on. My first tank lasts about 5 weeks then it takes about 1 1/2 to finsih the final 4-5 weeks.


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## spiderweber420 (Feb 17, 2011)

Very good thread. Subscribed, environmental control is my next lesson in canneducation can't wait. Definitely nominated for sticky every cannabis grower should read this man. Keep it coming dude


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## ExDex1x1 (Feb 17, 2011)

Thanks everyone for the support! I'll be adding more info in a few weeks. I'm writing up some more detailed information and planning on getting that $5/mo subscription next month so I'll edit in a big chunk of info all at once when I get that.

Let me guys know if there's any topics you'd like covered in more detail or anything that I was too fuckin high to explain clearly enough!

More to come soon!


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## ExDex1x1 (Apr 3, 2011)

Well I've been busy with real life crap for the last few weeks as well as my computer committing suicide so I haven't had any time or way of updating this thread. Now that I've got my new computer and (hopefully) some well deserved vacation time coming up (finally), I'll be adding to this thread some time soonish (if everything works out). In the meantime, shameful self-bump so maybe one or two more people can learn from this thread before it disappears to the depths of page 15 again.


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## WeeGogs (Apr 3, 2011)

christ, i am just gonna stick my plant outside in the sun with some pink plastic coloured flowers stuck on with superglue as a disguise, cos by the time i read through all this it will be fully grown and i will have forgotten what was written at the start and i would have to read it all again.


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## TokinDaily (Apr 3, 2011)

^ I bet that would work in some people. I had a 7 foot tree growing in my backyard last year, and most people didn't even realize what it was, or that it was real.


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## slygrow (Apr 16, 2011)

So I am venting through my dryer vent using a Y duct. The issue is that my exhaust fan is so powerful it pressurizes the dryer vent duct and send the smells back up into my dryer, so it smells like I'm growing inside my dryer. I tried using a one-way flap in that duct which did keep probably 90% of the odor out of the dryer, but then when you run the dryer it gets HOT as the duct flapper thing is restricting the airflow from the dryer. I don't want any fires etc. and am wondering if anyone else has found a way to successfully use the dryer vent for both growing and drying clothes without having to disconnect / reconnect each time the dryer is used....which is what I'm doing right now.....


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## ExDex1x1 (Apr 27, 2011)

slygrow said:


> So I am venting through my dryer vent using a Y duct. The issue is that my exhaust fan is so powerful it pressurizes the dryer vent duct and send the smells back up into my dryer, so it smells like I'm growing inside my dryer. I tried using a one-way flap in that duct which did keep probably 90% of the odor out of the dryer, but then when you run the dryer it gets HOT as the duct flapper thing is restricting the airflow from the dryer. I don't want any fires etc. and am wondering if anyone else has found a way to successfully use the dryer vent for both growing and drying clothes without having to disconnect / reconnect each time the dryer is used....which is what I'm doing right now.....


Personally I used to do this when I had a smaller grow. Haven't had experience with this issue since i was only using a 250cfm exhaust there wasn't a pressure issue due to smaller scale. I would consider trying to place your y closer to the actual exhaust point of the duct, the closer the better. If that doesn't work you could try putting a valve of some sort in the duct so instead of connecting and disconnecting you just flip a lever when you need to run your dryer.

you could also attach a booster fan on the end of your y split. This would cost a bit more but definitely solve your problems with air going back in your duct.


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## fallinprince (Apr 28, 2011)

Sticky vote FOR SURE


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## htroff420 (Apr 28, 2011)

Good shit, thanks man


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## ExDex1x1 (Apr 29, 2011)

WeeGogs said:


> christ, i am just gonna stick my plant outside in the sun with some pink plastic coloured flowers stuck on with superglue as a disguise, cos by the time i read through all this it will be fully grown and i will have forgotten what was written at the start and i would have to read it all again.


well to each his own. I personally think if you're going to grow do it right, and if you aren't willing to pay attention to the details on the most basic components of your grow op you'll run into problems down the road. Preparation and thorough planning often shine through in the final product. The whole stick it in the dirt and see what happens method is fine if you dont mind wasting years tinkering around instead of learning from the experience of others.


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## pain4life (May 13, 2011)

Great post! New to the site and when I find articles like this it makes me want to pull up a chair and stay a while.


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## ExDex1x1 (May 13, 2011)

pain4life said:


> Great post! New to the site and when I find articles like this it makes me want to pull up a chair and stay a while.


 
Glad to hear it! Sorry haven't updated the original post but really anything I haven't covered is more of a specific question thats tough to generalize. Glad too see so many people getting some use from this guide!


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## saganist (May 14, 2011)

Exellent post man, there is so much bad information on ventilation here its astonishing. People often just assume they will need a bunch of A/C running, or worse set up their room assbackwards so that they use a bunch of A/C that they don't really need. reps to you


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## loudpac (Aug 5, 2011)

nice< exactly what i've been looking for...
appreciate the info and extra tips, all of it was very useful...


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## motoman73 (Aug 5, 2011)

Hey Great Post.... Thanks for taking the time to explain this to a newbie like myself. I just purchased a cabinet for a diy project, I am basically trying to copy SuperClosets Deluxe 2..0. I think I have a good plan set up for my project. I am just a little confused, I am going to be using a passive intake system and use a 4"carbon filter with fan to extract air. Is the rule that I need three 4" intakes. I appreciate all your help...


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## AfricanHerbs7man (Aug 17, 2011)

much love to you friend....... this is a jewel ...each one teach one .... good karma .. Peace!


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## ExDex1x1 (Sep 20, 2011)

Sorry this guide has been sitting here collecting dust the last few months! I've been super busy irl, new house, new city, new job, ect. 

Thanks so much everyone for the support and I'm glad to see it's been helping a few people out here and there! 

Happy growing!


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## ak.fortyseven (Sep 20, 2011)

View attachment 1796505View attachment 1796501 



heres a couple diagrams to bascally give an idea on setup.
the first one is for a combination of filter and cool tube, the second is a split filter tube set-up.


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## ExDex1x1 (Dec 18, 2011)

ak.fortyseven said:


> View attachment 1796505View attachment 1796501
> 
> 
> 
> ...


Thanks for taking the time to draw up these diagrams they look great! +1 for you sir!


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## foreverflyhi (Jan 4, 2012)

hey so here is my current led/hps grow tent set up. After reading ur thread im a little more confused then ever, haha. ok so i own -
4x4x8 dr120
4 inch inline fan
600 cooltube hps
360 watt led penetrator
2 oscilating fans
2 cfm booster fans 70cfm maybe a little more
hepa organic air filter
6 inch and 4 inch ducting
3 trainwrecks and 1 sfv18 smartpots 5 gallon veg 6 weeks SCROG
1 loving supporting girlfriend

keep in mind lights on are at night AND i use the heat from the tent to warm my room
ok so here is how i have my setup i use the inline fan that sucks cool filtered air from my window, blown right underneath the thick canopy, 
i have one booster fan suckin hot air out the cool tube,but at the same time sucking cool air in from the window. (this is where one of my bigger heat problem might be at)
then i have one booster fan throwin out hot air from the top of the tent. I KNOW I NEED TO INVEST IN A CARBON FILTER, WILL DO SOON.
so i never peak over 82 degrees and it never gets under 74 degrees, leds due produce heat plus i think my booster fan isnt strong enough to suck hot air out the cooltube? and also maybe my booster fan isnt enough to suck hot air out at the rate im blowing coo air in?
anyways IM HIGH.
let me know what yall think????? im open to anything OH AND I HAVE A CO2 SYSTEM, I KNO I CANT RUN IT IN HERE, BUT IF ANYONE KNOWS SOME WAY TO RUN EVERYTHING THAT WOULD BE NICE! also have better pics, if yall intersted i can post more laterz
peace from ALL OF CALI


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## ak.fortyseven (Feb 10, 2012)

Np man, been offline for a few months


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