Sweaters

One of the best ways to save energy is to turn the thermosat down a few degrees and wear an extra sweater. Wool, was invented by sheep thousands of years ago and works well for keeping warm. Also consider the saying: the best way to warm up your hands is to put on a hat.

Just a few degrees can make a dramatic difference in the amount of energy used for heating your home.

Electric Heat Pump

An electric heat pump is the best option for electric heating. The heat pump works by moving electricity from the outside inside. Since it moves heat and doesn't create it, it is more efficient than other types of heaters.

The bonus is that you can also use it for air conditioning in the summer.

And yes, it still works even if it is cold outside. It makes the cold air colder.

Note that cost-wise a natural gas heater is probably cheaper, but as natural gas is a limited resource, it isn't included here as being fossil free.

Passive Solar

In the winter time a good way to collect heat energy is to open the shades and let sunlight warm your house during the day. This is a great way to collect solar energy that is 100% efficient.

If you are designing the house yourself, this technique can be augmented by careful window placement and by using materials that absorb heat during the day and release it at night. If you have an existing house, deciduous trees can be an effective way to provide shade in the summer and allow in sunlight in the winter.