Trying to cobble together a decent meal from the leftovers and random sauces in your refrigerator? Don't just stand there gazing into the glow. The University of Florida's Institute of Food and Agricultural Sciences estimates that 7% of a refrigerator's total energy use is the result of opening its doors. Though you obviously need to open your fridge to grab food, try to plan meals ahead or after taking a quick glance inside. According to building-science consultant Michael Blasnik, placing hot food in the fridge is the worst thing you can do if you want to keep your refrigerator running efficiently. You could open the refrigerator door hundreds of times before you'd waste the energy you do by putting a pot of hot soup into the refrigerator, Blasnik told Phys.org.It might seem like a chore to plug in your microwave every time you need to heat up some leftovers then unplug it when you're done, but leaving your gadgets connected to power at all times wastes electricity. According to the Department of Energy, electronics and appliances use energy even when they're turned off. That's true of phone chargers, laptops, televisions, curling irons, and kitchen appliances. Connecting your devices to a power strip can make it easier to turn off multiple unused items in one go. The next time you're whipping up something tasty on the stove, remember to use a lid. According to the Department of Energy, covering what you're cooking means that the food will cook faster, which allows you to use less energy in the process. Matching the size of the pan to the size of the heating element is also a good energy-saving strategy. Unless you typically watch your favorite shows in a super bright space, you can probably stand to turn down the brightness on your television. In fact, the Department of Energy has advised that switching your set to the home or standard setting can reduce your TV's energy usage by up to 30%. The average dishwasher uses about 1,800 watts of electricity to complete one wash and dry cycle. That's about $66 per year if you run your dishwasher once daily, according to the online tool EnergyUseCalculator.com. You can save serious money on your electric bill if you make sure to only use your dishwasher when it's completely full. If you just need to clean a few cups and plates, you're better off giving them a quick scrub in the sink. According to the US Department of Energy, your dishwasher's drying cycle is a sneaky energy waster. Rather than using valuable energy to dry your dishes, simply transfer them to a drying rack on your counter or give them a quick wipe with a clean dishcloth. You can even just open the dishwasher door and allow the dishes to dry in place before putting them away. Most modern washing machines can actually get your clothes perfectly clean with cool water. According to Energy Star, a government-backed energy-efficiency program, water heating uses about 90% of the energy it takes to operate a clothes washer. If you're trying to eliminate oily stains, washing with warm (not hot) water will do the trick. Homeowners looking to lower their energy bills should consider replacing older, outdated thermostats with modern, programmable versions. These allow you to make sure you're not heating or cooling an empty house during the workday. If you opt for a smart thermostat, such as Nest, you can control the temperature remotely in case you wind up arriving home later than usual. We all know how tempting it can be to linger under a hot shower on a chilly morning. However, those extra minutes in the steaming water can add up when it comes to your energy bill. According to the Department of Energy, water heating can amount to 12% of a household's energy bill. Try hopping out of the shower sooner to cut back on energy waste, or consider adding a low-flow aerator to your shower head to reduce the water flow. If your heating, ventilation, or air-conditioning system relies on air vents, you could be wasting energy by not keeping those vents clean. Clogged or dirty vents means that it takes more energy to heat or cool your home, according to the Department of Energy. Even scarier, letting debris build up in your vents can also lead to mold growth or vermin. Incandescent bulbs aren't very energy efficient. In fact, they haven't been manufactured in the US since 2014, and governments around the world have begun to phase them out entirely. Halogen incandescents, compact fluorescent lamps (CFLs), and light-emitting diodes (LEDs) use between 25% and 85% less energy. They also last 25 times longer. Buying in bulk and freezing groceries for the future is a good way to save some cash, but running a stand-alone freezer on empty is akin to throwing those savings down the drain. On average, a modern chest freezer consumes about 200 watts per day, which translates to about $14 per month, according to EnergyUseCalculator.com. If there's no food inside your stand-alone freezer, you're jacking up your monthly energy bill for no reason.