Smart bulbs, low-flow showerheads, smart thermostats, and other energy-saving devices can help lessen gas and electric usage, but they require some sort of upfront investment. Instead, try tweaking some of your daily habits, which can lower bills from as little as a few bucks a month to as much as a few hundred dollars a year.
You’ve probably been nagged by a loved one to turn off the lights when you leave a room, but here, Wirecutter experts offer several other pain-free (and often cost-free) suggestions that take the sting out of your monthly bills.

1. Open and close curtains, shades, and blinds strategically
Don’t leave your windows untouched! Take advantage of solar heat. 
2. Deal with drafty windows and doors
Applying weather stripping around old windows and door frames can improve your home’s insulation, but it can also be expensive and time-consuming.
3. Keep windows clean and remove the screens
They block substantial amounts of passive solar heat from entering your home.
4. Cook with countertop appliances
If you already own smaller electric appliances—like a toaster oven, air fryer, rice cooker, or an electric pressure cooker such as the Instant Pot—consider using them instead of your larger electric oven or range. 
5. Use a space heater (wisely, and not too much)
The infrared technology in space heaters is designed to heat people and objects, not space, so they’re best used as a spot treatment for situations like warding off a chill in a drafty home office.
6. Lower the temperature on your water heater
 Water heaters are often set very high: 140 °F or sometimes much higher.  Then a mixer lowers the water temperature before it’s sent to your various fixtures. 
7. Wash laundry in cold or warm water instead of hot
Making the switch on your washing machine from hot water to warm or cold can cut a load of laundry’s energy use in half
8. Vacuum forced-air grates
If your home is heated through forced air, make sure to vacuum the intake register covers. 
9. Instead of raising the thermostat at night, add more bedding
Shivering in bed is a flat-out miserable experience, but brisker air (around 60 to 67 °F) actually helps lower your core temperature, which is part of the body’s natural sleep cycle. 
10. Stash extra blankets and sweaters around the house
Your mom was right. You should just put on a sweater—but keep it in a place where you’ll actually use it. 
Mentioned in New York Times