Two years ago we enclosed the lower porch. The porch faces directly South. In winter the sun lowers in the sky, penetrates the windows, and heats up the enclosed porch. Even though the high for today was 52 F, the lower room got up to 74 F today.
We open the lower doors and all the heat in the enclosed porch (solarium) enters our home and rises to the upper floors. We have a remote thermostat to let us know the temperature in the solarium. When the temperature in the solarium rises above our home's inside temperature, we open the lower doors.
So far today the temperature in our home has risen from 65 F to 69 F just from the free heat we're harvesting in the solarium. Eventually today our home's temperature rose to 72 F. If you have an opportunity to face a building with windows facing south in winter, you'll reap the benefits of free solar heat. This is what is referred to as passive solar.
Today I worked on modifying my butter dish templates and tomorrow I'll make a few more butter dishes. Thanks for reading and for all your comments.