Whole House Generator Cost Calculator
Find out what a whole house generator costs. Pick your home size and power needs to get a fast, simple price estimate.
Standby Power Engineering & Utility Codes
National Fire Protection Association (NFPA) and National Electrical Code (NEC) guidelines for generator placement.
Clearance & Setback Codes
Minimum 5 feet from operable windows and doors; minimum 18 inches from non-combustible exterior wall assemblies per NFPA 37.
Whole-Home 200A ATS Transfer
Service-entrance rated automatic transfer switches ensure instantaneous sub-10 second failover when grid utility supply drops.
Fuel Supply Pressure
Requires 5 to 7 inches water column (W.C.) natural gas pressure and minimum 280,000 BTU meter delivery capacity under full load.
Mechanical Estimation Methodology
Curated by the Residential Remodeling & Construction Estimation Standards Desk.
Utility calculations incorporate published Generac and Kohler equipment list rates, regional master electrician hourly scales, and municipal mechanical inspection schedules across all 50 states. Estimations assume residential single-phase 120/240V utility service.
Electrical Interconnection & Automatic Transfer Switches (ATS): Under National Electrical Code (NEC) Article 702 guidelines for optional standby systems, transfer equipment must automatically disconnect the home electrical load from the normal utility power supply before connecting generator power, preventing dangerous backfeeding onto utility distribution lines. Sizing a whole-home 200-amp service-rated ATS requires matching the generator's emergency power capacity to the coincident peak demand of continuous mechanical loads, including electric heat pumps, air conditioning compressors, well pumps, and refrigeration circuits.
Fuel Delivery & Gas Plumbing Parameters: Natural gas and propane vapor plumbing lines require pressure regulators and pipe sizing compliant with NFPA 54 (National Fuel Gas Code). Generators operating at full load draw 280,000 to 350,000 BTU/hr, mandating dedicated 1-inch or 1-1/4 inch gas lines from the utility meter with minimum supply pressures of 5 to 7 inches water column (W.C.).
Frequently Asked Questions
How much does a whole-house generator cost installed in 2026?
Turnkey installation of a 22kW air-cooled natural gas or propane standby generator with a 200-amp whole-home automatic transfer switch (ATS) averages $10,500 to $13,800, including gas plumbing, electrical trenching, and local permits.
What size generator do I need for a 2,500 square foot home?
For a 2,500 sq ft home with central air conditioning (3 to 4 ton compressor), electric well pump, and refrigeration, a 22kW standby generator provides whole-home coverage without load shedding.
How much does natural gas line trenching and plumbing cost?
Connecting the generator to the existing gas meter requires high-volume poly or black iron pipe. Typical underground trenching and piping costs $30 to $45 per linear foot, with average 20-foot runs totaling $700 to $900.
Audit & Verification Summary (Residential Remodeling & Construction Estimation Standards Desk): All whole house generator capacity estimates, automatic transfer switch specifications, and fuel piping costs are modeled according to NEC Article 702, NFPA 54 standards, and certified master electrician billing telemetry.