Whole-House & Supplemental Generator Sizer

1. Enter Heavy Inductive Loads

Central A/C Condenser Size: Select system size to load typical Locked Rotor Amps (LRA).

A/C Locked Rotor Amps (LRA Data Tag): Found stamped directly on your outdoor condenser data plate.

Central A/C Electronic Soft Starter:

240V Large Window / Through-Wall A/C Units: Heavy 240V room conditioners used in workshops, master suites, or additions.

120V Standard Window A/C Units: Standard 15-amp bedroom/living room window units.

Deep Well Submersible Pump:

2. Critical Household Circuits

Kitchen Refrigerator & Deep Freezer (800W Run / 1,600W Surge) Basement Sump Pump 1/2 HP (1,050W Run / 2,200W Surge) Gas/Propane Furnace Blower (800W Run / 1,400W Surge) Electric Water Heater Element (4,500W Continuous / No Surge) LED Lighting, Network Router & Home Office (750W Continuous)

3. Electrical Sizing & Hardware Specs

Recommended Generator Capacity Rating:

0 kW Running / 0 kW Surge

Total Continuous Running Load (with 1.25× Safety Buffer):

0 W (0.0 kW)

Includes NEC 125% continuous-duty capacity buffer.

Worst-Case Motor Startup Surge Demand:

0 W (0.0 kW)

Calculated assuming highest concurrent motor startup.

Required Transfer Switch & Power Inlet Box Tier:

30 Amp (7,200W Max)

NEMA Configuration: L14-30P Twist-Lock (30A 120/240V)

Verified Hardware & Connections

Transfer Hardware

Manual Transfer Switch Kit

Pre-wired subpanel interlock kit matching your calculated electrical service amperage tier.

View Matching Transfer Switches

Hookup Cable

Generator Power Cord & Inlet Box

Weatherproof 4-prong cord and outdoor power inlet box matching your calculated amperage rating.

View Matching Hookup Kits

Power Generation

Matching Dual-Fuel Generator

Heavy-duty generator capable of handling both continuous house loads and motor inrush surges.

Browse Matching Generators

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Safety Disclaimer: Calculations generated by this application are mathematical approximations intended strictly for planning and estimation purposes. Real-world electrical loads, motor locked-rotor amperages, and site configurations vary. Always verify wiring, breaker sizing, and interlock installation requirements with a licensed electrician and local building codes before connecting any auxiliary power source to a building panel.