Best way to prepare window air conditioner for the winter?

November 10, 2005 7:19 AM

Best way to prepare window air conditioner for the winter?

After much gnashing of the teeth and yelling of expletives I finally managed to get an air conditioner mounted in a window off of my home office this summer. My windows are normally too large for a window mounted unit and I had to Macgyver up a large wood shim and other stuff to get the air conditioner to fit snugly.

Now that it's getting cooler out, I'm faced with the daunting possibility that I might have to uninstall the unit - something I'm loathe to do as it was a huge amount of work to install in the first place.

Can anyone offer advice on the best way to winterize this unit *without* removing it? Can I just wrap the inside part with thick plastic to keep drafts and the cold air out, or will this not be workable?

Note that we don't pay for energy costs (radiator heating) but I'd still like to find some balance between energy conservation and maintaining my sanity...

posted by theNonsuch to home & garden (5 comments total)

Those plastic window slips that you shrinkwrap with a hair dryer will help reduce the cold by insulating the space with air (which happens to be an excellent insulator). Not only could you use it on the wooden gap, but perhaps the A/C itself.
posted by furtive at 7:25 AM on November 10, 2005

To protect the unit itself, Home Depot (and similar stores) sells what amounts to an A/C cozy: A thermal cover for the outside of the unit that sticks beyond the wall of the house. You'll need the dimensions of your unit before going to the store, as they come in different sizes.

During a winter a couple of years ago, this probably saved our unit during a particularly vicious cold-snap.
posted by thanotopsis at 7:34 AM on November 10, 2005

furtive writes "(which happens to be an excellent insulator)"

Air is only a good insulator when it's still, convection currents in any vertical space wider than about 12mm drastically reduce the insulative properties of air.

Your A/C unit itself won't be harmed by even prolonged sub zero temperatures. However an A/C window unit is both made of metal, a good conductor of heat, and is minimally insulated. The physicist model of an A/C unit would be a metal plate in the window hole covered with a sheet of cardboard. Assuming you aren't in some place like Victoria, a cozy type cover will be a big improvement. You can make a custom cover out of the metallicized plastic bubble wrap they sell for insulating crawlspaces and hotwater heaters and some aluminum duct tape.

Also for comfort you want to make sure there are no drafts. If there are any cracks in your wood wedge fill the spaces with caulking or spray foam. The latex minimally expanding style is best for this use and it not as tenacious as the polyurathane and it won't buckle your window.
posted by Mitheral at 8:13 AM on November 10, 2005

Home depot sells winterizing covers for window air conditioners for ten bucks.
posted by winston at 10:33 AM on November 10, 2005

Related question--we're planning on removing our window unit, and storing it in our uninsulated shed until next summer. Is there anything I should to to prepare it?
posted by MrMoonPie at 11:42 AM on November 10, 2005