Change something. Watch what happens.

What this model leaves out

• Weather is synthetic. Each day is generated from monthly climate normals for one city per zone. Real years have longer droughts, deeper cold snaps and stranger weeks.
• The house is one room. Heat moves through walls, roof, floor, windows and air leaks as a single space with one temperature. Real homes have cold corners, stratified air and thermal bridges through framing.
• Water and food settle once a day. Rain, use and harvest are counted daily. Pipes, pressure, water quality and treatment are not modeled at all.
• Solar is simplified. No shading from trees or hills, no wiring losses by length, no charge-controller limits, and snow sliding is a rule of thumb.
• Batteries don't age. Capacity loss over years, cell balance and charge rates beyond a simple limit are left out.
• People are predictable. Everyone follows the same daily routine. Real habits, guests, illness and holidays change loads and water use.
• Gardens are averages. No pests, disease, soil building or crop-by-crop timing. Year-one gardens often yield less.
• Costs are ranges. They are national ballparks, not quotes. Labor, permits, shipping and local prices vary a lot.
• Safety is not modeled. Electrical faults, fire, carbon monoxide and structural loads are outside this model. Those need licensed professionals.

Every parameter lives in one documented object with a source key, and teaching simplifications are labeled. See how the model works, parameter by parameter and Sources.