66 free tools · 7 focused sections
Energy & Electrical calculators
Estimate energy production, connected demand, circuit performance, lighting needs and preliminary heating or backup-power capacity.
8 calculators
Insulation & heat loss
Insulation quantity, R-value, duct loss, window loss and building-envelope planning.
25 calculators
Heating & cooling
Heating and cooling capacity, filters, equipment sizing, comfort and running costs.
9 calculators
Solar energy
Solar array sizing, tilt, batteries, self-consumption, savings and payback.
6 calculators
Batteries & generators
Backup runtime, charge time, generator size, fuel and operating time.
4 calculators
Lighting
Room, workshop, landscape and energy-saving lighting estimates.
9 calculators
Electrical loads & appliances
Electrical load, voltage drop, EV charging, appliance cost and electricity use.
5 calculators
Ventilation & fans
Air changes, exhaust, whole-house fans and ventilation runtime.
About these calculators
Air-compressor tank fill time, air-compressor running cost, solar panel row spacing, solar battery payback, HVAC filter cost, battery cost per cycle, insulation installation cost, attic insulation, duct air velocity, electric space-heater cost, heating and cooling, solar, generators, lighting, electrical loads, running costs, ventilation, energy savings and backup-power calculators. Each tool provides a task-specific estimate, explains its assumptions, and rounds purchasing quantities where appropriate. Supplier specifications and local requirements remain the final authority.