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  1. #1
    Join Date
    Sep 2018
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    You will never be happy trying to convert a window unit. Heres Why.

    Reading through endless... even hundreds of posts in various forums to see HVAC pros shooting down window unit conversion ideas is what prompted this dangerous little experiment.

    Taking a week to develop a very basic understanding on how these units operate, combined with a desperate but not critical want for a cold Phoenix Arizona garage/shop, I successfully converted a cheap, ugly, noisy window unit into a silent, discreet indoor unit for under 300.

    The picture at first glance is what id imagine seeing in the garage of a cheap skate meth head neighbors garage who... yes. But in reality, i knew from the get go that an inverter mini split system will be the solution. i Considered this more of a semi-controlled learning experiment, but soon after starting realized it was ultimately a huge fire hazard and risk to not only my home but my neighbors as well. Not cool.

    Total costs were as follows:

    New in box fridgidaire 10,000 btu casement AC - $100
    Broan 15" 1600 cfm Attic Fan - $69.99
    25 ft 12" Insulated flex duct - $62.99
    2 x Sheets galvanized HVAC sheet metal - $ 16.99 Each
    HVAC Tin Tape - $10.99
    1 Gallon Mastic - $8.99

    My understanding of this prototype would be that the slight negative pressure created between the inline 1600 cfm Attic fan and the exhaust of the unit would increase its efficiency and reduce noise. Both of which i believe happened. What i did not consider was the heat rating for the attic fan internals, and the likely fire hazard presented by that detail. i did not take a temp reading, but from the metal fan shroud and back, it was way hot too the touch. surprisingly not the case from anywhere before that. So that immediately destroyed my hopes and dreams.

    Upon realizing this, i placed an Axis low latency network camera with a time stamp facing the outdoor exhaust, attaching a few small ribbons as flow indicators to be sure the video would not freeze without my knowledge. Painting this scene an entire 301" on my garage wall with a conference projector... to be sure it wasn't blowing a flame clear across my side yard into my neighbors bathroom window. Configured scene changing and tamper alarms to alert via loud Siren/red flashing should anything within the cameras view become abnormal that i happen to miss. Meanwhile i was inside the garage within arms reach of a fire extinguisher and the unit itself for about 12 hours a day, 7 days total. reloading rifle ammunition... with well over 200 lbs of various gunpowder types / roughly a million or so primers next to me.

    Moral of the story is this, You can jerry rig something on the cheap to cool ya down. Itll sound like a no brainer when all you want is to be in your natural habitat even if its 120 outside and 140+ in your garage. Hell, it may even work in the end, mine did. i set it to 72 and the space never got above 76 at the highest temps peaking 119 outside. Of course that was if i started it at 6am. BUT, not once did i actually get to enjoy it. i was watching and waiting... 12 hours a day, fully expecting this thing to combust. in hind sight, even if i caught a fire the second it started, id have been lucky to contain it. Dumb.

    Or it may have gone to serve me reliably for a decade. But im just not willing to risk something so easily avoidable to save a few hundred bucks.
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  2. #2
    Join Date
    Mar 2016
    Pahrump, NV
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    The best part is the cardboard!
    It's an upside down world we live in.

  3. #3
    Join Date
    Sep 2018
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    Thread Starter
    That was simply to suspend the metal sheet in the mastic because I was clueless on how to form dimensional objects with metal, let alone seamless ducting. Still am

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