Some of the appliances that use a lot of juice: forced air furnaces (blower motor), electric water heaters, electric dryers, electric ranges, dishwashers. ...and air conditioners, of course, but those are out of season. Some of the more powerful desktop computers, if they’re hooked up much, will use 100 watts or more...huge cost if left on for many watt-hours each day. A laptop will save big there, or a laptop mainboard in a desktop box with a small screen.
The electric company gives discounts for using appliances during off-peak hours.
Use them at night when possible. With natural gas, dress warm and lower the thermostat or shut it off.
Utility bills don’t have to be prohibitive if you plan ahead.