How Many Solar Panels Do I Need to Power a House?
A home using 900 kWh a month in a location with 4.5 peak sun hours needs about an 8.2 kW system, or 21 panels of 400 W. Here is the formula and a chart.
HVAC & Energy
What Size Air Conditioner Do I Need? BTU by Room Size
A 150–250 sq ft room needs about 6,000 BTU, and a 450–550 sq ft room about 12,000 BTU. Here is the full chart and the adjustments that matter.