Another super-easy trick: Bolt the door. “Locking the door closes it all the way to seal it against the weather stripping,” said Brittany Bailey, a licensed contractor and founder of PrettyHandyGirl.
Plug up drafty holes
If you’ve tackled the door and windows and still feel a draft, use this test to find the source: Wet your hand with water, then talk a walk around the room. Drafts can come from unexpected spots, like near the plumbing under the kitchen sink, around electrical sockets, from non-working fireplaces, and more — basically, any place that leads outside.
For out-of-the-way spots, Ms. Bailey recommends filling the gaps with expanding spray foam, an easy project that your landlord should be grateful for. (Bonus: It’ll keep out bugs and other critters.) For electrical sockets, Mr. Lipford suggests fitting a pre-cut gasket behind the outlet cover. If you have a drafty decorative fireplace, cut a piece of foam core to fit the back or opening to block the cold air.
Put down area rugs
If your floors feel cold, put down a rug. It sounds simple, but it’s more helpful than you may think. “Not only will a rug keep your feet from feeling cold, but it actually add a layer of insulation,” Ms. Bailey said. In especially chilly rooms like the bathroom, kitchen or ground-level spaces, add a rug with a rug pad underneath it, too. “Double the insulation!”
Get the hot air flowing
If you have central heating, it only works if there’s a free flow of heat into your rooms. If you don’t have air returns in each room, keep your doors open so your heating unit can warm your entire space efficiently.
If you find one room consistently cooler than others, adjust the vents redirect more heat to flow into the room.
Give your radiator an assist
A hack to get a little more heat from your radiator: Tape a piece of aluminum foil behind the radiator to reflect heat into the room instead of into the wall. “It sounds gaudy, but it works well and you’ll never see it,” Mr Lipford said.
And resist turning your radiator into a bookshelf: Heat rises, so you’re blocking the most natural pathway of warm air.
Rearrange the furniture
With any kind of heating system, make sure you’re not physically blocking the heat from getting into the room. “I can’t tell you how many times a tenant has complained that the heat’s not working, and I find out that there’s a sofa on top of the vent,” said Mr. Manfredini.
Move your furniture away from air vents and radiators so they have room to breathe. Even if your living room furniture isn’t blocking vents, consider scooting everything toward the center of the room in wintertime. “It’s always going to be colder around the perimeter,” Mr. Lipford explained.
Circulate warm air
If you have high ceilings and a ceiling fan, switch the fan to run in reverse during the winter. On a low setting, the fan will create a mild updraft that pushes the warm air down from the ceiling back into the room. “This costs pennies a week,” said Mr. Lipford.
Turn down the thermostat
While some apartment buildings operate on a single thermostat, single-family rentals and newer apartment buildings tend to let renters control (and pay for) their own heat, said Mr. Lipford. So take my dad’s advice: Put on a sweater!
Learning to live in a chillier space is a surefire way to save on your energy bill. The Department of Energy recommends setting your thermostat at 68 degrees in the winter for maximum energy savings. If you can lower your home’s temperature an additional seven to 10 degrees for eight hours a day (as in, when you’re sleeping or at work), you can save up to an additional 10 percent on your energy bill.
There is a threshold, though: Don’t turn the heat down more than 10 degrees if it’s only for a few hours, because it’ll take too much energy to heat your space back up. If you can, automate it with a smart or programmable thermostat. “Something like 60 percent of homes now have programmable thermostats, but many people still don’t use them,” Mr. Manfredini said. If you don’t, you may be able to install an inexpensive model yourself. (Just get permission first or save the old one to reinstall when you move.)
Spot-heat zones you use most
For nighttime, turn down the heat and outfit your bed with a cozy down comforter or heated mattress. Wirecutter, the New York Times product review site, recommends the Snowe Down Comforter for a durable, well-priced comforter and the Sunbeam Premium Quilted Mattress Pad for even more warmth.
If you have a room that always feel chilly, warm it with a space heater while you’re using it. “These use about the same amount of energy as a refrigerator, but that’s much less energy than warming up the whole house to make one room feel comfortable,” said Mr. Manfredini.
Wirecutter’s pick for the best space heater is the Lasko 754200 Ceramic Heater. Just be sure to use the same precautions with a space heater as you would with a lit candle: Never run it while you’re sleeping, don’t leave the room when it’s on and use caution when kids are around.
The same way humidity can affect the “real-feel” outside temperature in summertime, adding humidity to cold air makes it feel warmer inside. Moisture in the air holds onto heat better, keeping it warmer longer, and making it feel warmer on your skin, too. Wirecutter recommends the Honeywell HCM-350 Germ-Free Cool Mist Humidifier as the most effective, leakproof and easy to maintain option.
Use nature to your advantage
Especially in the winter, when the sun is low in the sky, you can get a lot of heat through south-facing windows. During the day, open curtains or blinds, then close them at night to keep that warm air in. Consider thick, lined curtains for extra insulation at night. “They don’t have to be thermal, just thick enough to block a draft,” said Ms. Bailey.
Finally, the next time you’re looking to move, ask the landlord what the average energy bill is before you sign the lease. In Mr. Lipford’s experience, the cost can vary by almost $100 a month even in similarly-sized homes, depending on how energy efficient they are.