Site & utilities estimator · Updated June 2026
Whole House Generator Cost & Sizing Calculator
A whole house generator costs $6,000 to $25,000 installed, with most homeowners paying $10,000 to $15,000. But before cost, get the number that matters most: the right size in kW for your home. Answer a few questions below for a personalized size recommendation, then an instant installed cost estimate.
Part 1: Size your generator
Part 2: Estimate installation cost
Enter your home's square footage
We'll recommend a generator size in kW, then estimate your installed cost.
- Most 2,000-2,500 sqft homes need a 16-24 kW generator for whole-house coverage
- Essential-circuits-only coverage needs roughly 30-40% less capacity
- The national average installed cost is $10,000-$15,000
- EV chargers and electric heat significantly increase sizing needs
What affects generator cost?
- Size (kW) — The biggest cost driver, though larger systems cost slightly less per kW.
- Brand tier — Premium brands add 25-35% but offer longer lifespans and better load management.
- Fuel type — Propane can add thousands if a new tank is needed; natural gas uses your existing line.
- Distance from panel/meter — Longer trenching runs for gas and electrical lines add real cost.
- Site conditions — Rocky soil or difficult access can increase installation labor.
- State — Labor costs in California and the Northeast run 20-30% higher than Midwest states.
What size whole house generator do I need?
Sizing depends primarily on your home's square footage and whether you want essential-circuit backup or full whole-house coverage, including central AC. As a starting reference:
| Home size | Essential circuits | Whole-house coverage |
|---|---|---|
| Under 1,500 sq ft | 10–12 kW | 16–18 kW |
| 1,500–2,000 sq ft | 12–14 kW | 18–20 kW |
| 2,000–2,500 sq ft | 14–16 kW | 20–24 kW |
| 2,500–3,000 sq ft | 16–18 kW | 22–26 kW |
| 3,000–4,000 sq ft | 18–20 kW | 24–30 kW |
| 5,000+ sq ft | 22–26 kW | 36–48 kW |
Square footage is only a starting point, not the final answer — electric heat, EV charging, and multi-zone AC systems all add meaningful load. A Level 2 EV charger alone adds 7,200–9,600 watts of continuous demand, which is why our calculator above adds capacity for each of these factors rather than relying on square footage alone.
How much does a whole house generator cost in 2026?
A whole house generator costs $6,000 to $25,000 installed, with most homeowners paying $10,000 to $15,000 for a properly sized system. Budget projects using smaller standard-brand units can start around $6,000-$8,000, while large premium systems for bigger homes can reach $30,000+. Use our calculator above for an instant estimate based on your specific recommended size.
Whole house generator cost calculator — by size
| Generator size | Estimated installed cost |
|---|---|
| 10–14 kW | $7,500–$11,000 |
| 16–20 kW | $10,500–$14,500 |
| 22–26 kW | $13,500–$18,500 |
| 30–38 kW | $18,000–$25,000 |
| 40kW+ | $24,000–$32,000+ |
Natural gas vs. propane: which fuel is better?
Natural gas is typically 30-40% cheaper to run than propane, and if you already have a gas line, installation is simpler since there's no fuel storage to install — the supply is automatic and effectively unlimited. Propane is the better choice if natural gas isn't available in your area; it works anywhere but requires installing and maintaining a tank, which can add $1,800 to $3,500 to your project if you don't already have propane service. Both fuel types work well with standby generators — the right choice usually comes down to what's already available at your property.
Standby vs. portable generators
This calculator covers standby (whole-house) generators specifically — permanently installed units that start automatically within seconds of an outage and run on natural gas or propane with no manual refueling. Portable generators are a different category: manual setup, gasoline-powered, limited to select circuits via extension cords or a transfer switch, and typically cost $500 to $3,000. If you only need short-term backup for a few essential items rather than automatic whole-home coverage, a portable unit may be a more affordable starting point.
Is a whole house generator worth it?
For many homeowners, yes. Consumer Reports and Remodeling magazine have both cited whole house generators as offering a strong return, with some estimates suggesting up to a 150% return on investment and roughly a 5% increase in home value. Beyond resale value, the practical case is straightforward: standby generators last 15-30 years or 10,000-30,000 running hours, and most residential units only run 50-200 hours per year even in areas with frequent outages — meaning a well-installed system can provide decades of reliable backup power.
Frequently asked questions
What size generator do I need for a 2,000 sq ft house?
Most 2,000 sq ft homes need a 16-20 kW generator for whole-house coverage including central AC, or 12-14 kW if you only want to power essential circuits. Electric heat, EV charging, or multiple AC zones increase this significantly.
How do I calculate whole house generator size?
Start with your home's square footage to get a baseline range, then add capacity for high-demand items: roughly 5 kW for electric heat, 8 kW for a Level 2 EV charger, and 4 kW for multiple AC zones. Our calculator above does this automatically.
What is the average cost of a whole house generator?
The national average installed cost is $10,000 to $15,000, with total costs ranging from $6,000 for smaller basic systems to $25,000 or more for large premium installations.
Is natural gas or propane cheaper for a whole house generator?
Natural gas is typically 30-40% cheaper to run than propane. However, if you don't have an existing natural gas line, installing one can cost $500 to $2,000 or more, which may offset the savings compared to propane in some situations.
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Disclaimer: All generator size and cost estimates are for informational purposes only based on average 2026 US installer rates and general sizing guidance. Accurate sizing requires a professional load calculation of your home's specific electrical circuits — this calculator provides a planning-stage estimate, not a substitute for a site assessment. Always obtain multiple quotes from licensed, insured generator installers before proceeding with any project.