Whole-House Generator Cost: Standby and Portable Options
What Does a Whole-House Generator Cost?
A whole-house standby generator costs $3,000 to $15,000 installed in 2026. The generator unit runs $2,500–$10,000 depending on capacity. Installation — including the transfer switch, concrete pad, gas line connection, and electrical work — adds $2,000–$5,000. Portable generators cost much less ($500–$3,000) but require manual setup and can’t power your entire home.
After major storms and grid failures in recent years, generator demand has spiked. Homeowners in states with frequent power outages — Texas, Florida, Louisiana, the Northeast ice belt — increasingly view standby generators as essential infrastructure rather than a luxury. If you work from home, have medical equipment that requires power, or live in an area where outages last days rather than hours, a generator is worth serious consideration.
Generator Cost by Type
| Generator Type | Power Output | Unit Cost | Installed Cost | Powers |
|---|---|---|---|---|
| Portable (gas) | 3,000–7,500W | $500–$1,500 | N/A (DIY setup) | Essentials only (fridge, lights, chargers) |
| Portable inverter (gas) | 2,000–6,500W | $800–$3,000 | N/A (DIY setup) | Essentials + sensitive electronics |
| Standby (natural gas) — small | 10–14 kW | $3,000–$5,000 | $5,000–$8,000 | Essentials + AC or heat |
| Standby (natural gas) — medium | 16–22 kW | $4,000–$7,000 | $7,000–$11,000 | Most of the house |
| Standby (natural gas/LP) — large | 24–48 kW | $6,000–$15,000 | $10,000–$20,000 | Entire house including AC, EV charger |
Standby vs. Portable: The Real Differences
Standby Generators
Standby generators are permanently installed outside your home, connected to your natural gas or propane supply, and wired into your electrical panel through an automatic transfer switch (ATS). When power goes out, the generator detects the outage and starts automatically within 10–30 seconds. When utility power returns, it shuts off automatically. You don’t touch anything.
This automation is the key advantage. Standby generators protect your home even when you’re not there — pipes don’t freeze, sump pumps keep running, refrigerators stay cold, and security systems stay active. For homeowners who travel, have vacation properties, or simply don’t want to deal with manual generator setup at 2 AM during a storm, standby is the right choice.
Portable Generators
Portable generators cost 70–80% less but require manual operation: wheel it outside, start it, run extension cords or connect to a manual transfer switch, refuel every 6–12 hours, and monitor for carbon monoxide. They can’t power central AC or most heating systems, and they’re loud (65–80 dB vs. 55–65 dB for standby units).
Portables make sense for: occasional use (1–2 outages per year lasting under 24 hours), camping and job sites, renters who can’t install permanent equipment, and homeowners on tight budgets. For $500–$1,500, a quality portable (Honda EU series, Westinghouse iGen) keeps the essentials running during short outages.
Sizing Your Generator
Undersizing is the most common and most expensive mistake. A generator that can’t handle your load will overload and shut down — or worse, damage connected appliances and the generator itself. Here’s how to size correctly:
| Appliance/System | Running Watts | Starting Watts |
|---|---|---|
| Central AC (3-ton) | 3,500 | 7,000 |
| Furnace blower | 500–800 | 1,000–1,500 |
| Refrigerator | 150–400 | 600–1,200 |
| Sump pump (1/2 HP) | 800 | 1,200 |
| Well pump (1/2 HP) | 1,000 | 2,000 |
| Electric water heater | 4,500 | 4,500 |
| Lighting (10 LED bulbs) | 100 | 100 |
| Microwave | 1,000 | 1,000 |
| EV charger (Level 2, 32A) | 7,700 | 7,700 |
Essentials only (lights, fridge, furnace, sump pump): 10–14 kW standby generator
Essentials + central AC: 16–22 kW
Whole house including AC, water heater, and cooking: 22–36 kW
Whole house + EV charger + workshop: 36–48 kW
Most homes do well with a 16–22 kW standby generator. This powers the essentials, central AC (the biggest single load), and most daily-use appliances. Load management (the generator prioritizes circuits and sheds non-critical loads automatically) lets a smaller generator handle a larger home — a 16 kW unit with load management can handle what a 22 kW unit does without it.
Installation Components
Automatic Transfer Switch (ATS)
The ATS sits between your electrical panel and the utility feed. It monitors utility power and switches to generator power when it detects an outage. Cost: $500–$1,500, included in most standby generator installation packages. Whole-house ATS units switch all circuits simultaneously. Load-management ATS units prioritize critical circuits and add non-essential loads gradually.
Concrete Pad
Generators sit on a level concrete or composite pad outside the house. A 3×4-foot pad costs $200–$500 poured, or you can buy a pre-cast GenPad ($100–$300). The generator must be at least 5 feet from windows, doors, and soffit vents (per code) to prevent exhaust from entering the home, and 18 inches from the house wall for airflow.
Gas Connection
Natural gas generators tap into your home’s gas supply. A plumber runs a dedicated gas line from your meter to the generator. Cost: $300–$1,500 depending on distance. Your gas meter may need an upgrade if the generator’s BTU demand exceeds the meter’s capacity — the gas company handles this, usually at no charge with advance notice.
Propane generators use a dedicated propane tank (250–1,000 gallon). Tank cost: $500–$2,500 (owned) or $0–$100/year (leased from a propane supplier). A 500-gallon tank runs a 20 kW generator for 5–7 days at full load. Propane is the better option for rural areas without natural gas service. Check fuel availability in your state.
Electrical Work
The electrician installs the transfer switch, connects the generator’s output to the switch, and runs control wiring. If your panel is full, a sub-panel ($300–$800) may be needed for generator circuits. Most installations require a permit ($100–$300) and inspection. Total electrical labor: $800–$2,000.
Fuel Costs and Maintenance
Running Costs
| Fuel Type | Cost per Hour (Half Load) | 24-Hour Outage Cost |
|---|---|---|
| Natural gas (20 kW) | $1.50–$3.00 | $36–$72 |
| Propane (20 kW) | $2.50–$5.00 | $60–$120 |
| Gasoline (portable, 7.5 kW) | $1.50–$3.00 | $36–$72 |
| Diesel (standby, 20 kW) | $2.00–$4.00 | $48–$96 |
Maintenance Schedule
Standby generators run a weekly self-test (10–15 minutes automatically, you’ll hear it once a week). Annual professional maintenance costs $150–$300 and includes oil change, filter replacement, spark plug inspection, battery check, and load testing. Most dealers offer annual maintenance contracts.
DIY maintenance (oil, filters) costs $50–$100/year in parts. The oil change interval is typically every 100–200 hours of operation or annually. Air filters and spark plugs last 200–400 hours. Keep the area around the generator clear of debris, snow, and vegetation for proper airflow. Include generator maintenance in your home maintenance budget.
Top Generator Brands
| Brand | Price Range | Reputation |
|---|---|---|
| Generac | $3,000–$15,000 | Market leader (70%+ share), wide dealer network, good warranty |
| Kohler | $4,000–$15,000 | Premium build quality, quieter, commercial-grade components |
| Briggs & Stratton | $3,000–$8,000 | Good value, solid residential line |
| Cummins | $4,000–$12,000 | Industrial heritage, excellent engines, smaller dealer network |
| Champion | $3,000–$7,000 | Budget-friendly, decent quality, shorter warranty |
Generac dominates the residential market and has the largest installer network. Kohler is the premium choice — quieter operation, better build materials, and longer component life. For most homeowners, Generac offers the best value. If you prioritize quiet operation (neighbors close by) or plan to keep the generator 20+ years, Kohler is worth the premium.
Generator and Home Value
A standby generator adds $3,000–$5,000 to home value in areas with frequent outages — effectively recovering 30–50% of installation cost at resale. In areas with reliable power, the value added is less. Generators are most valued in:
- Rural areas with long outage response times
- Coastal regions prone to hurricanes
- Ice belt states with winter storm outages
- Homes with sump pumps (where outage = flooding)
- Homes with well water (no power = no water)
A generator won’t make or break a home sale, but it’s a differentiator in markets where outages are common. Listing it prominently in the MLS description catches the eye of buyers who’ve experienced extended outages. Learn more about how upgrades affect your home’s worth at the renovation ROI guide, and factor it into your home equity calculations.
Frequently Asked Questions
How long can a standby generator run continuously?
Natural gas generators can run indefinitely as long as the gas supply holds (utility gas is essentially unlimited). Propane generators run until the tank is empty — a 500-gallon tank lasts 5–7 days at half load for a 20 kW generator. Diesel generators run 24–48 hours on a built-in tank and need refueling. Manufacturer recommendations suggest an oil check every 24 hours of continuous operation and an oil change every 100–200 hours.
How loud is a standby generator?
Most residential standby generators produce 55–70 dB at 23 feet — roughly the volume of a normal conversation to a loud dishwasher. Generac units tend to run 65–70 dB; Kohler units run 55–65 dB. Noise ordinances in some communities set limits (typically 65–70 dB at the property line). Position the generator as far from your bedroom and your neighbor’s bedroom as practical. A sound-attenuating enclosure ($500–$1,500) reduces noise by 5–10 dB.
Do I need a whole-house generator if I have solar panels?
Solar panels alone don’t provide backup power — they shut off during outages (grid-tied systems are required to disconnect for utility worker safety). To use solar during outages, you need a battery system (Tesla Powerwall, Enphase IQ, $10,000–$20,000). A generator provides immediate, reliable backup regardless of weather or time of day. Many homeowners pair solar + battery for daily savings with a small generator for extended outages.
What size generator do I need for a 2,000 sq ft house?
Square footage alone doesn’t determine generator size — electrical loads do. A 2,000 sq ft house with gas heat and a 3-ton AC needs a 16–20 kW generator. The same house with electric heat, an electric water heater, and an EV charger needs 30+ kW. Have an electrician perform a load calculation based on your actual electrical usage. Run the numbers through our calculate monthly costs to see how financing a generator fits your budget.
Can I install a standby generator myself?
No — standby generator installation requires licensed electricians and plumbers, permits, and inspections. The transfer switch connects to your main electrical panel (electrocution risk), the gas line carries explosive fuel (fire/explosion risk), and improper installation voids the warranty and insurance coverage. Always use an authorized dealer/installer. The installation cost ($2,000–$5,000) includes all licensed trade work, permits, and warranty registration.
How often should a standby generator be serviced?
Annual professional service ($150–$300) covers oil, filters, spark plugs, battery, and a full-load test. Between services, the generator runs a weekly self-test automatically. Replace the battery every 2–3 years ($50–$100). The engine should last 10,000–30,000 hours depending on the model — for a home generator that runs during outages and weekly tests, that’s 25–50 years of service life. Factor this into your long-term home maintenance plan.