• In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to get air conditioning where window units aren't practical.


    1. If there's no existing wall vent, use a jigsaw to cut a 4-inch-diameter hole through an exterior wall.
    2. Apply silicone caulk to rear flange on wall vent.
    3. From outside, slide wall vent through hole in wall; secure with stainless steel screws.
    4. Twist and lock the flexible duct to the exhaust port on rear of air conditioner unit.
    5. Connect the duct end to the wall vent and seal with foil duct tape.
    6. Plug air conditioner unit into an electrical outlet.
    7. Turn on unit, then set thermostat and, if desired, the automatic timer.
    • 10 to 20 minutes if using existing wall vent; 1 to 2 hours if cutting and installing a new wall vent
    • Difficulty: Easy
      even if you've got to cut a wall-vent opening

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      Video Directory

      Selected Topic/Section

      Tools List

      • jigsaw
        used to cut vent hole in wall for 4-inch duct.
      • caulk gun
        Caulking gun with silicone caulk
      • drill

      Shopping List

      1. Portable air conditioner

      2. Wall vent

      3. 4-inch-diameter flexible exhaust duct

      4. Foil duct tape,
      for connecting duct to wall vent

      5. 1-inch stainless steel screws,
      used to secure wall vent