You wouldn't know this if you lived where there's no snow but snow reflects a lot of sun so build to access the sun's warmth in the winter makes a lot of sense when you live up north.

There is a trick to it though - you need to be able to close off the glassed area at night or loose all your day-time gains. The EarthShip designs are the most efficient at doing this and they use south-facing greenhouse areas to filter water, grow food and light the interior areas.

 

A little more complex is the double envelope from Earth Shelters as it balances out the seasonal differences in temperature. Some add-on designs will take heat from the summer attic and store it for winter use.

 

Solar Hot water designs are available all over the internet.