Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?

Passive solar heat gain (winter)

Admits solar heat deliberately and keeps it. The winter half of a pair with summer shading.

Solutions

• South-facing glazing sized for winter gain: Windows on the south side, sized and placed to let in the winter sun. The sun is low in winter, so its light reaches deep into the rooms and warms them for free
• Slate-clad solar air heater (wall-mounted thermosiphon collector): A glazed box on a south wall with a dark slate plate inside. Room air enters at the bottom, is warmed by the sun-heated slate, rises and flows back into the roo