Heat loss through windows

Talking to my dad:

Question: what happens when we have large glass walls/windows and all the heat gets lost through them?
The major heat loss in our house is apparently though the windows.

+One alternative is no windows. We could replace the windows with giant television screens! I'm very much against this. Lack of real light, and too many lcd screens.

+Or we could have insulating windows. For example:
--shutters over the windows
--fill the windows with an insulating gas
--have a setup that pumps tiny packing foam balls into the space between window panes (and can pump them out again)

Options such as shutters and packing material will block light as well as heat, so they would be closed when no-one is home or during the night.

These solutions could either be hand motivated or automated. Automated solutions could integrate the shutter/vaccum controls could integrate with the temperature sensors and be part of the passive heating and cooling system, or just be time based like current termostate setups.