What size generator do I need for emergency backup?

What size generator do I need for emergency backup?

When the grid goes down, the right generator keeps your home steady. The key is matching size to your real needs, budget, and comfort level. Below, you’ll find a simple sizing method, an interactive calculator, and three clear emergency scenarios—each paired with dependable Mighty Generators models. We’ll touch on craftsmanship, smart features (remote monitoring, electric start), and true value at each level—from budget-friendly portable units to quiet, automatic home standby systems.

How to size your generator the simple way

You don’t need a complicated spreadsheet—just a clear list and a little headroom. Follow these three steps:

1. List your critical items. Start with fridge/freezer, lights, sump pump, well pump, garage door, internet/routers, medical equipment, furnace fan, and any window or mini-split AC you plan to run.
2. Find wattage. Check appliance labels or manuals. Note two numbers when possible: running watts and starting (surge) watts. Motors like pumps and fridges spike at startup.
3. Add up running watts, then add the single highest starting surge on top. Finally, add 20% headroom for comfort and to avoid pushing the generator at full load nonstop.

Tip: If you plan to run central AC, electric heat, or a large well pump, move up a size. Many homeowners choose a generator slightly larger than their bare-minimum total. Recent buyer trends show a strong shift toward higher-capacity models for better reliability during longer outages.

Interactive emergency sizing calculator

Use this quick calculator to ballpark your size. Enter your own wattages from labels. It adds running watts, adds the largest surge once (so you don’t double-count), and applies a 20% buffer.

What your number means: If your estimate lands near a category boundary, step up to keep noise and fuel use lower at the same comfort level—and to handle seasonal peaks.

Three clear emergency scenarios (and what size you really need)

• Essentials only (fridge/freezer, lights, phones/routers, a small pump): Many homes land around 2,000–5,000 watts. Value-focused buyers often choose the 5 kW class to gain extra breathing room and avoid running at full tilt.
• Essentials + comfort (add a window AC, microwave, coffee maker, or well pump): 5,000–9,000 watts is the sweet spot. Current trends show strong demand in the 4–8 kW range because it balances power, runtime, and fuel use well.
• Whole-home (central AC, larger pumps, multiple circuits): 13,000–20,000 watts with an automatic transfer switch and a proper installation. Standby units take the stress out by starting on their own and running key circuits without manual steps.

Weather matters. In summer, AC draws can bump your number quickly. In winter, furnace fans and space heating do the same. If anyone in the home depends on medical equipment, size up modestly and consider a system with remote monitoring and automatic start for peace of mind. For circuit integration, review Generator Transfer Switches early in your planning.

Best generator picks by scenario and budget (craftsmanship + value)

Below are specific models sold by Mighty Generators. Each one is chosen for build quality, practical features, and strong value for its class. Click through for details, specs, and installation guidance—and keep your sizing notes handy as you compare.

Quick comparison matrix

Featured picks: craftsmanship, value, and key features

Briggs & Stratton 13kW PowerProtect Standby Generator

$4,460.00

Brand: Briggs & Stratton

Material: aluminum

• Compact design simplifies placement in tighter lots and reduces install headaches
• Remote monitoring capability for status checks when you’re away

View Product

Cummins RS20A 20kW Home Standby Generator

$5,069.00

Brand: Cummins

Material: aluminum, galvanized steel

• Automatic activation during power outages for true set-and-forget operation
• Remote monitoring capability and quiet performance for neighborhood-friendly backup

View Product

Ford FG11050PBE 11,050W Dual Fuel Portable Generator

$1,139.95

Brand: Ford

Material: metal, plastic

• Dual fuel flexibility (gasoline or propane) to match what’s available
• Portable, robust design that handles higher comfort loads

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Pulsar PG7500 7,500 Peak Watt Gas-Powered Portable Generator

$999.95

Brand: Pulsar

Material: metal

• Electric Push Start (with recoil backup) for fast, no-hassle starts in bad weather
• Durable construction and multiple outlets for household essentials

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Pulsar PG5250 5,250W Portable Gas-Powered Generator

$599.95

Brand: Pulsar

Material: metal, plastic

• Versatile outlets and extended runtime for core essentials
• Easy mobility with a durable wheel kit for quick deployment

View Product

Extra views: product image gallery

Want a closer look? Tap any image to open the product page.

Why these picks make sense right now

Homeowners want reliable power and smart fuel use. Portable units remain popular because they’re versatile and cost-effective, while standby systems are growing fast as weather events become more frequent. Market insights show strong interest in the 4–8 kW space for balance, with more buyers stepping up a size to ride out multi-day outages without stress. In short, a well-sized unit that’s a touch bigger than the bare minimum delivers better comfort, cleaner starts, and confidence.

How to match size to your home and gear

• Small homes or apartments: If you need to keep a fridge, lights, and a few devices going, a ~5 kW unit like the Pulsar PG5250 is a smart value pick.
• Suburban homes with a well pump or window AC: The Pulsar PG7500 moves you into the comfort zone with electric push start, so you’re not pulling a cord in bad weather.
• Flexible fueling for longer outages: Ford FG11050PBE runs on gasoline or propane. Dual fuel can be a lifesaver when gas lines are long or stations are closed.
• Whole-home coverage, set-and-forget: The Briggs & Stratton 13kW PowerProtect and Cummins RS20A 20kW start automatically, and both support remote monitoring for peace of mind when you’re away.

Fuel type choices (and why dual fuel can help)

Gasoline is common and easy to find—until a storm hits hard. Propane stores longer and can be simpler to manage in extended outages. Dual fuel is a smart hedge that gives you options when supply is tight. For a deeper dive, see our guide Propane Generators vs Gas Generators.

Transfer switches: the safe, clean way to power circuits

A transfer switch connects your generator to selected circuits in your panel, keeps your home safe, and prevents dangerous backfeed. It also makes life easier—no extension cord jungle. Explore Generator Transfer Switches and talk with a licensed electrician for installation. Consider whether a manual or automatic switch fits your routine and whether you need 30A or 50A service for your loads.

Craftsmanship and materials

• Aluminum and galvanized steel enclosures (like on the Cummins RS20A) help resist corrosion outdoors. That’s long-term value in four seasons.
• Compact designs (Briggs 13kW PowerProtect) simplify placement near the home and reduce installation headaches.
• Durable frames on portables (Pulsar and Ford) are built to roll out quickly and handle rough conditions.

Standby vs. portable: which path is right for you?

• Portable: Lower upfront cost, flexible, and quick to deploy. Great for renters or owners who need essentials and a few comforts. See deals in the $501–$999 range.
• Standby: Higher initial cost, but automatic, quiet, and steady. Ideal for families needing seamless power or running larger loads. Browse Standby Generators and Home Backup Generators.

Medical equipment and sensitive electronics

If you depend on medical gear, plan a buffer above your minimum wattage and choose a system that starts reliably in the middle of the night. Remote monitoring on standby units adds a layer of safety. For sensitive electronics, look for “clean power” solutions (such as many standby systems or inverter-based portables) and use quality surge protection. For appliance-specific sizing, see our quick read: Choosing the Ideal Generator for Refrigerator.

Real-world planning tips

• Prioritize: Decide what you must run during week-long outages. That decision sets your size and fuel plan.
• Seasonal swing: AC and heat loads push sizing. If summers or winters are tough where you live, step up one size.
• Fuel storage: If you go portable, plan safe fuel storage and rotation. Dual fuel gives you options when supply is tight.
• Noise: Standby units like the Cummins RS20A are designed for quiet operation—helpful in dense neighborhoods.
• Test ahead: Do a dry run with your prioritized circuits so you know what to switch on—and what to leave off.

Safety musts

• Never run a portable generator indoors or in a garage. Keep it outside, away from windows, doors, and vents. Use battery-operated CO detectors.
• Use a transfer switch for home circuits. Avoid backfeeding through outlets.
• Let the generator cool before refueling. Use proper fuel containers and keep them away from heat sources.
• Use heavy-duty, outdoor-rated extension cords of the correct gauge for the load and distance.

Best picks by budget

• Under $700: Pulsar PG5250 — dependable 5,250W class with extended runtime and easy mobility. Solid essentials coverage at a sharp price.
• $700–$1,200:
  • Pulsar PG7500 — electric push start plus durable build for comfort loads.
  • Ford FG11050PBE — dual fuel flexibility and high wattage capacity.
• $4,000–$5,100:
  • Briggs & Stratton 13kW PowerProtect — compact standby with remote monitoring.
  • Cummins RS20A 20kW — automatic activation, quiet operation, and rugged aluminum/galvanized steel construction.

Whole-home reliability: why standby keeps winning

Standby generators are seeing strong growth. With more weather-related outages, many homeowners value systems that start automatically and run the home without manual work. Remote monitoring lets you check status while traveling. If you want a deeper look at one top brand, see Briggs & Stratton standby generators.

Where to go from here

• Shop the full lineup: Standby Generators | Home Backup Generators | $501–$999 Deals | Over $2000
• Learn before you buy: Product Guides | Why Invest in an Emergency Generator
• Plan your install: Generator Transfer Switches

Frequently asked questions

How much headroom should I add? A 20% buffer is a good starting point. If you’re in extreme heat or cold, size up another notch.

Can a portable unit power my whole home? Usually not. Portables shine for essentials and a few comfort items. For whole-home backup, consider a 13–20 kW standby system with a transfer switch.

Is dual fuel worth it? If you want options during a long outage, yes. The Ford FG11050PBE gives you gasoline or propane flexibility.

What about noise? Standby units such as the Cummins RS20A are built for quiet operation. Portables vary; place them outside, away from windows.

Do I need an electrician? Yes, for any transfer switch or standby installation. This keeps your home safe and up to code.

What’s the difference between running and starting watts? Running watts are the steady draw while an appliance operates. Starting (surge) watts are the brief spike when motors start. Size for your total running load plus the single highest surge, with headroom.

Do I need 120/240V output? If you plan to power well pumps, some HVAC equipment, or select large appliances through a transfer switch, 120/240V capability is typically required. Check your panel and loads with a licensed electrician.

Final sizing advice

Start with your real loads. Decide the minimum you need to stay comfortable. Add your biggest seasonal draw. Then choose an honest, well-built machine with the features that matter to you: electric start, dual fuel, or remote monitoring. If you want automatic peace of mind, a compact, aluminum-clad standby unit is hard to beat. If you want maximum value today and flexibility, a sturdy portable in the 5–8 kW class is the sweet spot for many homes.