Window air conditioning units work wonders in summer, but in winter, they should be removed and put in storage. Why? Because energy conservation, that’s why.
First of all, no matter how snugly your ac fits in the window—and let’s face it, it probably doesn’t fit very well at all—there’s still a draft coming through. Only a fully shut and locked window is truly sealed against the elements. Ask anyone who’s sensitive to drafts and they’ll tell you they feel one when they stand in front of a window with an ac in it.
Any sort of draft causes the energy output of your heating system to skyrocket because it’s constantly trying to compensate for that continuous flow of cold air. Taking out your window ac is the fastest, easiest, and most obvious way to stop drafts.
The more energy your heating system uses, the more money it costs to run it (obviously), but if you’re renting an apartment where “heat is included in rent,” you don’t notice that money blowing away in the winter breeze. But it absolutely is. When your lease renewal runs around, you’ll see that money again in the form of raised rent. When utilities are included in rent, the amount of rent reflects that. So if you’re causing your landlord to pay high utility bills for your unit by wasting energy, you can bet that your landlord will pass those costs onto you by raising your rent.
Now, there is another important reason to remove your window ac that applies only to those with radiator heat who have their ac installed directly above a radiator (which, if you have radiator heat, is probably exactly where you ac is… it’s more or less unavoidable). Radiators are made of cast iron and they can withstand a great deal, but one thing that is definitely a danger to them is the frigid cold air of deep winter in Pittsburgh. During extreme cold you should never open a window directly above a running radiator because that radiator can crack and leak. An ac inside a window directly above a radiator is pretty much the same thing as an open window above a radiator. If it gets cold enough, that little draft is going to crack your already overworked radiator.
Radiators are not easy to replace because, firstly they’re getting harder and harder to come by, and secondly the entire heating system has to be shut down to do the work. Then there’s the matter of repairing the damage from the leak. A single radiator can leak a whole lot of water and that water will not only destroy your flooring, it will destroy the ceiling in the apartment below yours. You can bet that if your radiator cracks because you opened the window, your landlord will charge for the full cost of repairs, and that’s going to add up to hundreds of dollars.
So when we say you should remove your window ac because it will allow you to conserve energy, what we mean is, you should remove your window ac because it will save you money.