Home backup is a different generator-buying problem than camping or jobsite use. You're sizing for sustained, multi-day operation through whatever the weather is doing. You're feeding circuits through a transfer switch or interlock. You need fuel storage that survives a regional outage. And you'll be running the generator outside your house but listening to it for hours, which means decibel level matters even if you're not at a campsite.
These five picks cover the realistic range of home backup needs, from essentials-only at 3,500W up to whole-home at 11,500W. Above that, you should be comparing portables against permanent standby installations — see whole-house vs portable.
Sizing for home backup
The right wattage for your home depends entirely on what you want to run. The realistic brackets:
- 3,500–4,500W: Fridge + freezer + furnace blower + lights + modem + sump pump + occasional microwave. No central AC, no well pump, no electric range.
- 5,500–7,500W: Essentials plus one window AC unit, or essentials plus well pump, or essentials plus brief microwave/coffee maker use without conflict.
- 9,000–12,500W: Central AC (typically 3-ton or smaller), well pump, electric range or water heater. Most homes can run "nearly normal" at this size.
Detailed sizing math is in generator sizing: how many watts.
The picks
Westinghouse WGen11500DFc
What it does well: 9,500 running / 11,500 starting watts on gas. 6.6-gallon tank for ~12-hour runtime at half load. Remote start key fob, electric start, transfer-switch-ready L14-30R outlet, digital display with hour meter for maintenance planning. Three-year warranty.
The trade-off: Open-frame and loud — typical for the wattage class. 200+ pounds with the wheel kit.
Champion 100165 (7,500W Dual Fuel)
What it does well: 7,500 running / 9,375 starting on gas. Volt Guard surge protector, electric start, three-year warranty plus Champion's lifetime free technical support — useful when something needs diagnosis. RV-ready 30A and transfer-switch-ready outlets.
The trade-off: Open-frame conventional design — louder than inverter equivalents and slightly higher THD (won't hurt fridges, lights, or fans; might cause modern smart-appliance hiccups).
Generac GP8000E
What it does well: 8,000 running / 10,000 starting watts. Generac's residential network means parts availability is excellent through dealers (not just mail-order). Electric start with idle control, hour meter, three-year warranty.
The trade-off: Single-fuel gasoline (no propane). Generac portables are not the same as their well-regarded standby generators — buy expecting standard mid-tier portable build quality.
Westinghouse iGen11000DFc Inverter
What it does well: Inverter-clean power (under 3% THD) at 9,000 running / 11,000 starting watts. Dual-fuel, electric start, remote start, transfer-switch outlets. The best choice if your home has substantial smart-appliance loads (modern fridge, electric range with electronics, HVAC controllers).
The trade-off: Significant price premium over the WGen11500 open-frame equivalent. The inverter benefit is real but not always necessary behind a transfer switch.
Champion 3500W Open-Frame Inverter
What it does well: 3,500 running / 4,500 starting watts — enough for refrigerator, furnace blower, sump pump, lights, modem, microwave (sequentially). Inverter-clean power, dual-fuel, electric start with remote fob, CO Shield. Significantly more efficient and quieter than 7,500W conventional generators when load is light.
The trade-off: Won't run central AC or a well pump. Best for homes where essentials-only coverage is the goal.
Why dual-fuel is the right answer for home backup
Three reasons we recommend dual-fuel almost universally for home backup:
- Propane stores indefinitely. Gasoline degrades in 30 days untreated, 12 months with stabilizer. A propane tank stored five years ago is still ready.
- Gas stations lose power during regional outages. The first thing to disappear when a hurricane or ice storm knocks out power is local gasoline supply. Stations can't pump without electricity.
- Propane burns cleaner. Less carbon deposit means longer engine life. If you're going to run a generator hard for multi-day stretches every few years, propane is gentler on the engine.
The transfer switch question
Powering individual appliances via extension cords from a generator parked outside works for emergencies. It's miserable for multi-day outages, dangerous for furnaces and well pumps that are hard-wired, and impossible for central HVAC.
The proper solution is a manual transfer switch or interlock kit installed at your main electrical panel by a licensed electrician. This lets you feed selected circuits (or the whole panel) from the generator via an inlet outdoors, with positive lockout that prevents backfeeding into the utility grid. We cover this in detail in how to connect a generator to your house.
Fuel storage planning
For a multi-day outage on a 7,500W generator at ~50 percent load, expect roughly 0.75 to 1 gallon of gasoline per hour. That's 18 to 24 gallons a day. Plan storage accordingly:
- Three to five 5-gallon stabilized gas cans, rotated through your vehicles to keep fresh
- Plus two to four 20-pound propane tanks, or a 100-pound stationary tank with a dedicated regulator hose
- Stored away from the house (codes typically require 10+ feet from living space)
- Stabilizer treatment (Sta-Bil, Star Tron) for any gasoline stored over 30 days
Frequently Asked Questions
What size generator do I need to power my whole house?
Depends on what's in your house. For essentials only (fridge, furnace, lights, sump pump), 5,500–7,500W is sufficient. For central AC plus a well pump plus all essentials, 9,000–12,500W. Above that, a permanently installed standby generator is usually a better solution than a heavier portable.
Can I run my furnace from a generator?
Yes if it's a gas furnace — the blower motor is 700 to 900 watts running. You'll need a transfer switch or interlock kit because furnaces are hard-wired, not plugged in. Pure electric furnaces (resistive heat) draw 10,000+ watts and aren't realistic to backup with a portable generator.
How often should I run a home backup generator just to keep it ready?
Run it for 15 to 30 minutes under light load every month. This keeps the carburetor wet (preventing varnish buildup), the battery charged, and surfaces wear on internals. Change oil annually or every 50 hours, whichever comes first.
Do I need a permit to install a transfer switch?
Almost always yes — transfer switches modify your electrical service entrance and most jurisdictions require a permit and inspection. Hiring a licensed electrician who handles the permit is the standard approach. DIY installation is illegal in most areas and voids most home insurance.
Will a portable generator damage my home's electronics?
An inverter generator (under 3% THD) is safe for any modern electronics. A conventional generator (8–25% THD) may cause flickering on LED lights and rough operation of variable-speed appliances. For home backup with significant electronics, prefer inverter or AVR-equipped open-frame units.