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Preventing Condensation in Outdoor Enclosure

  1. Jan 28, 2016 #1
    Hi, I have comes across bits and pieces of what I want to do online but haven't gotten the answers I need so I'm reaching out for help. This is my first post here.

    I'm planning to create a box to house an AV receiver outdoors (late spring/summer/early fall only in Maine) inside a screen porch. The box will need a door to open when in use to allow airflow and in the back a port for speaker wires and power cable/HDMI cable. Inside will also be a chromecast or amazon fireTV stick. It will get misted when it rains so the box should cover that base, however when the nights get cold I am imagining condensation will become a problem.

    1. If I placed a "seed starter" heated mat inside the enclosure (I have one that is 15 watts) on a timer to run from say 6pm to 10am inside a weather protected box with small air leaks, would that alone prevent condensation? I doubt 15 watts would overheat the receiver when it is off, and the box would be open while it is on with more airflow. But is 15 watts enough for a small end table sized enclosure? Does the internal box temperature just need to be literally 1 degree above outside temp at all times to prevent condensation? Im also wondering if the chromecast or fireTV stock on standby alone would create enough heat in the box?

    2. Is there a material I could line the box with on the sidewalls that would attract condensation to those areas as opposed to the metal case of the receiver? Condensation developed on this material could be captured by design.

    3. Desiccants seem like they would be a hassle. I would have to close the desiccant container up when the stereo is in use and open the container before closing the box up for the night. I would also need to ensure the box is near 100% sealed. Would a product like "Damp rid" which I use in my basement closet work well enough? This product would be a slower dehumidifier since I can use one in my basement for several months and just dump out the water it collects.

    The only risk for condensation for a receiver sitting outside (protected from rain) is when the ambient temperature raises faster than the receivers temperature can, because it is made of denser materials, right?

    Are there other properties of condensation that would make option 1 fail? Thoughts? Comments?
  2. jcsd
  3. Jan 28, 2016 #2


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    Gold Member

    An induced flow of air just a few degrees warmer than environment will usually minimise condensation .

    Basically a small electric fan and a low power heating element .
  4. Jan 28, 2016 #3


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    If you are just going to be using electricity to warm your AV receiver why don't you just use electricity to power it thus keeping it warm? Standby mode may draw enough. This may be one time that "Vampire" power might be a good thing.

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