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Thermal imaging

Discussion in 'Indoor Growing' started by GreenGro, Feb 6, 2007.


    GreenGro Well-Known Member

    Can anyone tell me how good thermal imaging technology actually is?

    If I were to use a 600 watt bulb in a roof space that was insulated what would be the chances of this being able to be picked up by thermal imaging cameras?

    And does anyone know if the ADF proof mylar actually prevents a thermal image being visible?

    Thanks for any help on this

    whitebombs Well-Known Member

    i am a cop and i think you are okay.

    bigbudeddie Well-Known Member

    Gotta love crook cops. I smoke to that. Do you honestly think that the money spent on such imaging devices would be used for a single 600w setup. I wouldnt think so, but what do i know im no fed.

    GreenGro Well-Known Member

    Well recently in our area cops have been using handheld imaging cameras to identify housefuls of shit. And then theres the storys of helicopters flying over looking for warm attics

    Ok so maybe im being a bit para but it comes with the territory :?

    xenu Active Member

    In a roof space, a FLIR will find a 400 Watt light, even behind insulation.

    A good FLIR unit can read people coupling.

    Scepter1987 Well-Known Member

    Like they said in another post like this one, they are not going to just randomly fly over your house searching for stuff, they must have a warent for that. I Believe.... May be wrong tho...


    green_nobody Well-Known Member

    A 600W bulb has a thermal fingerprint that for sure will show up in thermal cam if that roof got no insulation. that are thermals in the 2500-4500$ range and beyond, a normal sheriffs outfit won't spent that much normally. so put some r20 in and you cool, put some tight r40 up ant the have to move up to the 150,000+ range or they won't see shit. and the r40 cuts down on your heating bill big time too! :-)

    and the saves thing, submerge you project into the total underground;) move tho the basement, and seal it of maybe as well:-)

    mogie Well-Known Member

    [​IMG]Infrared cameras are widely used by law enforcement for border patrol, grow room confirmation, and other surveillance operations. There is legal debate as to whether this technology is intrusive or non-invasive.

    Growers fear IR because it?s difficult to ?hide? invisible heat. Protecting yourself against excessive heat emissions is a good defensive measure. This FAQ focuses on masking heat emissions.

    What is infrared?
    Light and heat energy warm objects, which then re-radiate excess energy. Some of this excess energy is emitted as low-energy infrared. IR is invisible to the naked eye, but can be displayed and measured by specialized cameras.

    What does Leo look for?[​IMG]
    Officers are trained to look for hot spots on walls and windows, unusually warm foundations, exhaust emissions from vents and chimneys, and warming trends typical of marijuana grow operations. Leo will wait until evening or early morning (when the grow is up to full temperature and the air is cool). He will also look for light leaks, smells and other info at this time.

    Note: Leo will try to image a suspected grow-op from all angles, but is only legally able to do so from public property (ie. Sidewalks, roads, public paths, etc).

    Note: power companies occasionally image power pole transformers to see if they are abnormally hot (problems), and to source power theft.

    Legal implications
    (ExpensiveCloset) "A thermal imaging scan does not intrude in any way into the privacy and sanctity of a home?the privacy associated with a home, are (not) threatened by thermal imagery." (US supreme court ruling)

    "The Supreme Court ruled 5 to 4 on June 11 [2001] that police cannot use infrared heat-detecting technology to gather evidence from a private home without a search warrant" High Times, October 2001 (Pg.20)

    In Canada, IR is used in the pre-investigation phase. Positive results can then be used to obtain a search warrant.

    Will Insulation help?
    Conventional insulation will help block IR, but it is probably not enough by itself. A fully insulated wall (R 40) will hold heat much longer than a window (R 2). Concrete is a good conductor of heat; after hours of HID lighting, foundations will become abnormally warm.

    Most growers flower at night to take advantage of the naturally cooler air; unfortunately, a warm grow house will radiate lots of thermal energy compared to the cool night air.

    How do I mask my heat emissions?
    Note: Small grows (under 2000w) would probably not emit enough heat to warrant the effort or expense.

    Note: Reducing grow room temperature will reduce heat emissions; however, the grow room will still be warmer than surrounding basement rooms.

    This technique creates a false wall to contain cold air. Interlocking rigid foam panels prevent hot grow room air from contacting and warming house walls. Cold air is blown into the gap between the foam and the walls for maximum protection. The wall?s exterior will appear ?cold? to an IR camera, indicating a negative for internal heat.

    · "Partial room" (insulate exposed walls only)
    · "Room in a room" (entire rooms are insulated)

    *Floor. Concrete foundations absorb heat readily. Build a sub floor to raise the entire grow off the floor.

    *Walls. Use interlocking 1.5 or 2? foam insulation along all exposed walls. Place the insulation 1-4? away from walls, fit foam panels from floor to ceiling (some cutting may be required), and blow cold air into the gap. Seal seams and corners with tape. Cover walls with Mylar to reflect heat back into the room.

    *Windows. Windows are essentially uninsulated, so you must fill the gap with insulation. Draw the curtains/blinds, add black poly behind, then add insulation.

    Drawing description[​IMG]
    A ? Public property that Leo can image from

    B ? Internal basement room. Grow room heat will still be noticeable, and this side needs protection.

    C -- ?Safe? basement rooms. Put ballasts and reservoir outside to minimize heat

    D ? Partially insulated growroom. The pink band is the interlocking foam insulation, the blue band is the cold air contained between the insulation and the house walls. The window on the bottom of the picture can be open to allow cold air to enter the air gap. Room temperature air can also be blown in from an adjacent basement room through a hole in the foam panels.

    Hiding the Exhaust
    Safely exhausting hot air is difficult; Leo looks for unusual heat emissions coming from opened windows, chimneys, dryer vents and other handy places. Note: running exhaust to outside sheds, barns and tree stumps is well known to Leo.

    Exhaust down the sewer[​IMG] Every house has a sewer vent standpipe. By venting down the sewer, the exhaust will be chilled and smell is distributed amongst you and your neighbors. The sewer cleanout access is often a 3-way 4? abs ?T? with a threaded cap somewhere in the basement. Remove cap, and hook your blower to the T (A 4? to 3? adapter funnel may be required) and run blower 24/7. This will not affect normal use of the sewer

    Cool exhaust with water
    Place a wet towel (wicking water from a tray underneath) partially over the end of the exhaust. Spraying water inside the exhaust pipe works as well.

    Underground exhaust
    Running the exhaust through a long, buried pipe helps to cool the air. Perimeter drains can be used for this.

    Water-cooled lights
    Running water cooled lights is very effective; IR heat from the lights are washed down the drain. Water cooled light systems are currently difficult to source, and have drawbacks including cost, condensation and leaks.

    Tools for the grower:
    Note: most ?night vision? devices use UV (ultraviolet) and not longwave IR detection.

    Engine heat ?guns?. +/- 1F. Numerical readout, laser pointer.
    "Night Vision" scopes, cameras and camcorders.
    Infrared film (Kodak High Speed Infrared Film 2481)
    Wavels and PapayaTwins like this.

    jasonxx420 Active Member

    OK here is the thing. I do Heating and air conditioning for a living. you have no idea how many heaters there are in attics and i grantee that a heater puts out way more heat than even a 1000 wt can put out so don't trip. all i would worry about is venting the room to keep the temp in check.

    Wavels Well-Known Member

    That was probably one of the most informative and interesting pieces I have ever read on any cannabis site!
    Thanks Mogie
    Mogies post:

    This is why I keep my indoor grows modest in size....two 400w and one 600w and assorted old style floros....
    Then I go nuts outdoors and look for mega size harvest...which is an inherently more stressful practice....but for me this works because of the way I spread the plants around in lots of different areas. I worry less about this than larger indoor grows I used to run.
    I am not in a friendly state!

    GreenGro Well-Known Member

    Thanks for all this help guys, nice article Mogie!

    Has anyone heard about the ADF (anti detection film) mylar? apparently it reflects 90 % of all heat signatures inwards and prevents detection by thermal imaging.

    You can see it for sale here Mylar, Trimming Machine, Propagators, Greenroom etc amongst other places. It seems to good to be true but then again are they allowed to make wild claims like this if they are not true? May well be worth a try I suppose just for extra peace of mind.

    mogie Well-Known Member

    All you need to know about Mylar

    Contributed by :Kermitt
    Submitted September 16, 2003

    Mylar reflects about 94% of the light.
    One of the best materials on the market for light proofing.

    Mylar is a product that serves many purposes. The insulation industry developed this product to withstand severe temperatures. It acts as a moisture barrier as well as a reflector. The United States Navy uses Mylar aboard all of its Freight ships, Cruisers, and Destroyers.

    Mylar comes in several different types:




    Dimpled Metalized is available also.

    Threaded Aluminized (reinforced)

    What we OGer's are interested in is the obvious, we want to wrap our grow space, large or small, with the best reflective material available. Aluminized or Metalized Mylar.

    Mylar is a chemical resistant, polyester film that is mostly tear resistant depending on mil. The reinforced Mylar is almost impossible to tear. It can withstand temperatures of up to 200 degrees Celsius, Mylar is also electrical resistant and fire retardant.

    Unlike foil, mylar lays flat without the crinkles and creases if handled with care. Mylar WILL not create concentrated hot spots.

    Material Gauges are as follows. 001", 002", 003", 004", 005", 007", 010", 014".

    Most Hydroponic shops only carry 001" and 002" mil. Which is all you need if your using as a grow room reflector. Mylar can be cleaned with Windex, alcohol or any other mild household cleaner. I use an antibacterial hand soap with warm water.
    PanamaRed766 likes this.

    mogie Well-Known Member

    Contributed by: Stickydank

    I've discovered the cheapest Mylar around-- only 2 bucks$! You save 18 bucks$ a roll! It?s a Christmas present wrapping Mylar called Polywrap

    - Waterproof
    - 50 square ft. a roll
    - 1 mil (@ .001 inch) thick X 3 1/2 ft. wide X 20ft long.

    Note: Only buy the very Bright and shiny Mylar-type wrapping!

    Hydrotech364 Gen Mod

    Is it true that they can tell where the plants are if you grow more than three together.or is that a wives tale spurred by flir technology???????

    TetraHyC Well-Known Member

    If they are going to use FLIR, they need a search warrant, if they have a search warrant they will just knock on your door.

    Hydrotech364 Gen Mod

    im talking about 400 yards from my house in the jungle.im in the us but its an awesome climate for it.they say weed gives off a certain signiature,is this true?i want these monsters close to each other because of security and drainage concerns.peace:bigjoint:
    Green on Green

    Green on Green Active Member

    "Gotta love crook cops. I smoke to that. Do you honestly think that the money spent on such imaging devices would be used for a single 600w setup. I wouldnt think so, but what do i know im a fed."

    Would have been soooooooooo hilarious
    Problem Child

    Problem Child Active Member

    I just thought of an excellent way to keep down the IR signature of a hot exhaust..

    I'm way into high performance cars, and an air to air intercooler would work wonders on a hot exhaust tube coming from a HID grow lamp. Just submerge a 4"in-out air to air intercooler in a tub of water (possibly chilled) inline with the exhaust flow, and presto! cold exhaust air. A cheap aluminum intercooler from eBay can drop air temps on a turbocharged car over 100 degrees, and that's just from moving air. water would cool it much much more efficently.

    PanamaRed766 Active Member

    nice work mogie, you answered quite a few of my questions (+rep). im ending my research and about ready to start growing.

    im gonna have a 5-10 plant basement grow w/ a 400w HPS light. after reading this my mind is a little bit at ease about ventilation but to make sure... how worried should i be about this thermal imaging?
    Last edited: Jun 6, 2008

    acidserum Active Member

    i simply don't have to worry about none of this shyt , i gro with 75 watts at night nd 35 at day

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