Build with precision.

Estimate room air-conditioner BTU size from room area, ceiling height, sun exposure, occupants, and heat gains.

Estimate generator running watts, starting watts, surge margin, and capacity fit from appliance load inputs.

Estimate collected rainwater from roof area, rainfall, runoff efficiency, tank size, demand, and overflow.

Estimate septic tank capacity from bedrooms, design flow, retention time, safety factor, and local minimum size.

Estimate solar system size, panel count, roof area, and offset from electricity use, sun hours, losses, and panel watts.

Estimate tank first-hour rating, tankless flow rate, peak-hour demand, and temperature rise from hot-water uses.

Free heat loss calculator using Q=UA∆T. Enter area, R-value, and indoor/outdoor design temperatures to get design hea...