The process of converting a house to renewable energy begins with:
1. Upgrading its passive solar features, then,
2. Tightening the envelope through adding insulation, upgrading windows, and so forth.
3. The next stage is adding solar hot water heating. Heating water accounts for a quarter to a third of energy usage in a home and using solar water heating can substantially cut the energy bill.
4. Then PV.
5. And then whatever is still needed.
Let's look at three options for adding solar water heating to our homes.