Home Standby Generators

Power outages are unpredictable. A two-hour blackout is an inconvenience. A multi-day outage in summer heat or winter cold becomes a genuine safety risk. Home standby generators solve this by automatically switching on the moment your grid power fails, running on natural gas or propane for days at a time, with zero manual effort required.

This guide covers the best whole-home standby generators for extended outages, what size you actually need, and what to look for before buying.

How to Choose the Right Size

Generator capacity is measured in kilowatts (kW). The right size depends on which appliances you need to run simultaneously during an outage. Here's a practical breakdown:

Capacity	Best For	What It Powers
10–14 kW	Small homes, condos, apartments	Lights, refrigerator, sump pump, a few outlets
16–20 kW	Mid-size homes (1,500–2,500 sq. ft.)	Central AC (up to 3 tons), kitchen appliances, lighting throughout
22–26 kW	Large homes (2,500+ sq. ft.)	Full HVAC (4–5 ton), electric water heater, multiple appliances at once
30+ kW	Luxury estates, high-draw setups	Multiple HVAC zones, pool pumps, Level 2 EV chargers

One important note: most generators produce 10–15% less power on natural gas compared to liquid propane. If you're running on natural gas, size up slightly to account for this difference.

The Best Home Standby Generators

1. Generac Guardian 24kW — Best Overall

Generac controls roughly 70% of the home standby market for good reason. The Guardian 24kW is the go-to choice for most homeowners. It handles full whole-home coverage for a typical family home, includes a 200-amp automatic transfer switch, and comes with Mobile Link Wi-Fi monitoring so you can check fuel levels and status from your phone.

• Output: 24 kW (LP) / 21 kW (NG)

• Noise level: ~67 dB

• Warranty: 5 years

• Fuel: Natural gas or liquid propane

• Estimated installed cost: $12,000–$15,000

Best for: Homeowners who want the most proven, widely-serviced option on the market.

2. Kohler 26RCA — Best for Premium Reliability

Kohler's standby generators are the preferred choice when reliability and power quality are the top priority. The 26RCA uses a commercial-grade engine, restores power in under 10 seconds (faster than most competitors), and delivers industry-leading voltage stability of ±1%. This makes it the safest option for homes with sensitive electronics, medical equipment, or smart home systems.

• Output: 26 kW (LP) / 24 kW (NG)

• Noise level: ~62–65 dB

• Warranty: 5 years / 2,000 hours

• Fuel: Natural gas or liquid propane

• Estimated installed cost: $15,500–$19,000

Best for: Homeowners in coastal or high-humidity areas, or anyone powering medical equipment or extensive smart home technology.

3. Cummins RS22 — Best for Extreme Weather

The Cummins RS22 is built to perform in conditions where other generators struggle. It starts reliably down to -22°F and operates at just 62 dB, making it one of the quietest standby generators available. Its commercial-grade construction makes it well-suited for long, multi-day outage scenarios in harsh climates.

• Output: 22 kW (LP) / 19.8 kW (NG)

• Noise level: ~62 dB (quietest in class)

• Cold-start rating: -22°F

• Fuel: Natural gas or liquid propane

• Estimated installed cost: $12,500–$16,000

Best for: Northern climates with severe winter storms, or homeowners in neighborhoods where generator noise is a concern.

4. Briggs & Stratton PowerProtect DX 26kW — Best Natural Gas Performance

Most standby generators lose 10–15% of their rated power when running on natural gas. Briggs & Stratton's NGMax technology eliminates this problem, allowing the PowerProtect DX to deliver full rated power on a natural gas line. It also comes with one of the longest warranties in the category, with some DX models offering up to 10 years of coverage.

• Output: 26 kW (LP and NG, no derating)

• Noise level: ~65–69 dB

• Warranty: Up to 10 years on DX models

• Fuel: Natural gas or liquid propane

• Estimated installed cost: $14,500–$17,000

Best for: Homes connected to municipal natural gas with no propane tank, where full output on NG is essential.

5. Generac Guardian 10kW — Best for Essential Coverage on a Budget

Not every home needs a whole-home generator. If your goal is keeping the refrigerator running, the lights on, a sump pump active, and a few key outlets live, the Generac Guardian 10kW covers all of that at a significantly lower cost. It's the right entry point for smaller homes or homeowners who want reliable backup without full-home coverage.

• Output: 10 kW (LP) / 9 kW (NG)

• Warranty: 5 years

• Fuel: Natural gas or liquid propane

• Estimated installed cost: $6,500–$9,500

Best for: Small homes, condos, or homeowners who only need essential circuit coverage.

Key Features to Look For

Automatic Transfer Switch

This is the device that detects a power failure and switches your home to generator power without any manual steps. All standby generators include one, but confirm the included switch matches your home's electrical panel (100A, 200A, etc.).

Remote Monitoring

Generac's Mobile Link, Kohler's OnCue, and similar apps let you check generator status, fuel levels, and run hours from your phone. Useful for multi-day outages when you may not always be home.

Fuel Source

Natural gas provides an effectively unlimited fuel supply during extended outages since it comes from the grid. Propane gives you independence but requires a large enough tank. For extended outages, natural gas is the practical choice.

Engine Cooling Type

Air-cooled engines cover most residential needs up to 26 kW. Liquid-cooled engines are found on 30+ kW units and are built for continuous multi-day operation in very hot climates without overheating.

Noise Level

Most standby generators run at 62–69 dB, similar to a normal conversation. If you're in a neighborhood with close houses or local ordinances, look for units rated at or below 65 dB. Cummins leads here.

Self-Test Cycle

Quality standby generators run a brief self-test weekly to ensure they're ready when needed. Look for models where the self-test schedule is customizable so it doesn't run at 3 AM or during dinner.

Brand Comparison at a Glance

Feature	Generac	Kohler	Cummins	Briggs & Stratton
Max Air-Cooled Output	26 kW	26 kW	22 kW	26 kW
Noise Level	57–67 dB	62–65 dB	~62 dB	65–69 dB
Standard Warranty	5 years	5 years / 2,000 hrs	5 years	7–10 years
Smart Monitoring App	Mobile Link	OnCue Plus	Yes	Symphony II
Full Power on Natural Gas	No (10–15% drop)	No (10–15% drop)	No (10–15% drop)	Yes (NGMax tech)
Power Restoration Speed	10–20 seconds	Under 10 seconds	Under 10 seconds	10–20 seconds

What You Should Know Before Buying

A standby generator is not a plug-in appliance. Installation requires a licensed electrician and, in most cases, a gas plumber. Permits are typically required. Budget for professional installation on top of the unit price, which generally adds $2,000–$4,000 depending on your home's setup.

Plan for annual maintenance, including oil and filter changes every 200 hours of operation or every two years. Most manufacturers recommend a professional tune-up yearly to keep the warranty valid.

Finally, check your local ordinances for setback requirements. Most municipalities require standby generators to be placed at least 18 inches from the home and 5 feet from any opening (windows, doors, vents).

The Bottom Line

For most homes, the Generac Guardian 24kW is the best starting point: proven, widely serviced, and feature-rich. If power quality and speed matter most (medical equipment, smart home systems), go with Kohler. For the coldest climates or noise-sensitive neighborhoods, Cummins is the clear pick. And if your home runs entirely on natural gas, Briggs & Stratton's NGMax technology makes it the most efficient choice.

Get quotes from at least two certified installers in your area before committing. Prices for the same unit can vary by thousands of dollars depending on your local market and electrical panel configuration.