Generator
Add the loads you want to run together, including the motor that needs the most power to start.
Open the calculatorFind your starting size.
Ten tools. Clear assumptions. A range you can discuss with your installer.
Central air conditioner
Start with your home and climate. Check the range before a contractor completes your load calculation.
Open the calculatorFurnace
Compare heating output with furnace input capacity. Your climate and building envelope make the difference.
Open the calculatorHeat pump
See cooling demand and winter heating demand separately, including a cold-weather capacity assumption.
Open the calculatorTank water heater
Size the busiest hour, then compare first-hour ratings on the EnergyGuide label.
Open the calculatorTankless water heater
Add simultaneous fixture flow and the rise from incoming water to the delivery temperature.
Open the calculatorSolar panels
Turn your electricity use into system capacity using a cached PVWatts production estimate.
Open the calculatorDehumidifier
Choose capacity from your room size and dampness using current ENERGY STAR pint ratings.
Open the calculatorWindow air conditioner
Use the ENERGY STAR room chart, then adjust for sun, people and kitchen heat.
Open the calculatorMini-split
Estimate cooling for the served room or open area. Each zone needs its own professional load calculation.
Open the calculator