Our active heating system consists of one wood stove: the "Pacific Vista" by Pacific Energy Fireplace Products Ltd.. This is a great stove, that heats our house up in no time - as long as the wood is well seasoned.
The "passive solar" design of our house allows for heat gains from the sun. The majority of our windows are on the south side of the house, with none on the north. We purchased Marvin "Integrity" windows, double-glazed, with low-E argon. These windows allow the heat from the sun in, and then keep a significant percentage of the heat inside. It's amazing how effectively this works. There were some sunny days this past winter where we didn't need the wood stove on at all, even though the temperature outside was around 0 degrees Celsius.
The "passive solar" principal is most effective when the north side of the house is protected from the cold northerly winds by coniferous trees. Deciduous trees on the south side will allow the sun through in winter, and provide shade in summer when the leaves are in full.
An even better way to maximize passive solar gain is to build the house into a south-facing hill, or provide a bank (or berm) of earth on the north side of the house. Earth is an excellent insulator and temperature regulator, keeping the house warm in winter and cool in summer. Although we don't have an earth-bermed house, we would suggest anyone look into it if they are planning to build an energy-efficient home.