About
Understand what shapes an energy choice before comparing costs or equipment.
Energy before equipment
Bring your consumption, available space and the question you want to resolve. The comparisons keep those inputs visible.
Keep quantities together
Change a value and follow its effect on quantities and costs, with the source and limit beside the result.
Know the site's limits
Use the result to prepare questions for a qualified site assessment; it is not permission to install or a promise of savings.