It’s difficult to determine what’s most awful about winter— the constant cold feet and hands, the unpleasant dread of stepping out of the shower, or the horror of opening a heating bill after a month of leaving the thermostat turned up overnight. Since hibernating for three months isn’t an option, the best way to cope is to make sure your living space stays as warm and toasty as possible without spending an arm and a leg or burning the joint down. You need to winterize that thing.
First, fix your windows. It should go without saying that being warm during the winter and leaving your window unit air conditioner installed year-round are mutually exclusive things. It should also go without saying that before cold weather hits, you should make sure that your windows are closed completely. Just because these things should go without saying doesn’t mean that everyone is some kind of astronaut genius who remembers things like the fact that their windows can open from the top and won’t spend an entire winter huddled under four comforters like the garbage dump hoarder from Labyrinth.
Next, cover your windows with some plastic. I can’t recommend 3M Window Insulator kits enough for cold weatherproofing; my mom always used them when I was a kid and they look a lot less junky than other windowcovering methods.
But you don’t need to stop there. Invest in some heavy curtains to further keep heat locked into your space, and leave the curtains open during the day, but closed at night, especially if the windows face East or South. This will not only give your neighbors the impression that you’re secretly Soviet spies having nighttime meetings, but it will allow heat from the sun to get in, and keep heat from escaping when it’s dark out.
If your place uses forced air heat (so if your heat comes out of the wall via vent), make sure the vents are clean. Pet hair and air flotsam can get trapped in there, and trapped junk in your vent will reduce the amount of hot air that actually gets to your chilly limbs.