Last verified: 12 November 2026.
The short answer
For most Hawaii homes, a 5,000-watt dual-fuel inverter generator is the sweet spot. It runs a fridge, lights, phones, Wi-Fi, and a CPAP machine, costs about $999, and runs on gasoline or propane. If you need to power more — a second fridge, a well pump, or window AC — step up to an 11,500-watt model at about $1,349. Whatever you buy, run it outside, at least 20 feet from the house. Never indoors, never in a garage.
How much power do you actually need?
Generators are sold by watts. Two numbers matter:
- Running watts — what an appliance draws while it runs.
- Starting watts — the short spike a motor needs when it turns on. A fridge needs far more power for one second at startup than it does while running.
Add up the running watts of everything you will run at the same time, then add the starting watts of the single biggest motor. Do not add every motor’s surge together — only the biggest one starts at a time.
| What you want to run | Running watts | Extra starting watts |
|---|---|---|
| Full-size fridge / freezer | 700 | 2,200 |
| Chest freezer | 500 | 1,000–1,500 |
| Sump pump (1/3–1/2 HP) | 800 | 1,300–2,400 |
| Well pump (1/2–1 HP) | 1,000–2,000 | 2,100–4,000 |
| Mini fridge | 75 | 400–600 |
| LED lights, phone charging, Wi-Fi, TV | ~100–300 combined | — |
| CPAP machine (no humidifier) | 30–60 | — |
| CPAP with heated humidifier | 60–100 | — |
| Oxygen concentrator | 300–600 | 600–1,800 (surge is 2–3× running watts) |
Wattage figures: Lowe’s / Generac sizing worksheet; CPAP and oxygen concentrator figures: emergencyenergy.co, 2026.
A typical “keep the food cold” plan: Fridge (700) + lights, TV, Wi-Fi, chargers (~300) + sump pump (800) = about 1,800 running watts, plus the fridge’s 2,200-watt startup spike — roughly 4,000 watts at peak. That is why a 5,000-watt generator covers most homes’ essentials, and why the common essentials range is 5,000–7,500 watts.
Note on fridges: Modern Energy Star fridges often draw less — about 150–400 running watts with a 600–1,200-watt surge. Check the label on your own fridge (usually inside the door or on the back) for the real number.
Medical devices need clean power. CPAP machines and oxygen concentrators usually need a pure sine wave inverter — that means an inverter generator, not a conventional open-frame generator. Talk to the device maker or your doctor before counting on a generator for medical equipment, and test the whole setup before storm season, not during it.
Gasoline, dual-fuel, or propane?
- Gasoline only. Cheapest to buy. But gasoline goes stale in 3–6 months, so you must use fuel stabilizer or rotate your stock. After a hurricane, gas stations may be closed or out of fuel.
- Dual-fuel (gasoline + propane). The best choice for most Hawaii homes. Run it on gasoline when that is handy; switch to propane when it is not. Propane never goes stale, so a tank can sit in the garage for a year and still work. Both models below are dual-fuel.
- Tri-fuel (gasoline + propane + natural gas). Useful only if your home is on a gas line. Most Hawaii homes are not — see the Hawaii note below.
Inverter vs. conventional
- Inverter generators make clean, stable power (under 5% total harmonic distortion, or THD). Safe for phones, laptops, TVs, and medical devices. They are also quieter and use less fuel, because the engine slows down when the load is light. They cost more per watt.
- Conventional (open-frame) generators are cheaper and tougher, but the power is rougher and they are louder. Fine for power tools and old fridges; not ideal for sensitive electronics.
For a home backup, buy an inverter generator.
Noise: how loud is it?
Noise is measured in decibels (dBA). A normal conversation is about 60 dBA. The Westinghouse iGen5000DFc runs at about 52 dBA — quieter than talking. Big open-frame generators run 70 dBA or more, which is about as loud as a vacuum cleaner and will annoy the neighbors at 2 a.m. If you live in a dense neighborhood or a townhouse complex, quiet matters.
Runtime: how long will it run?
Runtime depends on the tank and the load. The iGen5000DFc runs up to 18 hours at 25% load on a tank of gas. The WGen11500DFc runs up to 19 hours on its 9.5-gallon tank. Real-world runtime is shorter when you run more things. Plan your fuel: for a multi-day outage, figure on 5–10 gallons of gasoline per day for a 5,000-watt unit, or one 20-pound propane tank (about 4.7 gallons) every 8–10 hours at moderate load.
The models we checked (prices verified 12 November 2026)
Prices were checked on the retailer’s own website on 12 November 2026. Prices can change, and Hawaii store prices may vary — check before you buy.
Best for most homes: Westinghouse iGen5000DFc — $999 at Home Depot
- 5,000 peak watts on gasoline (3,900 running); 4,500 peak on propane (3,500 running)
- Dual-fuel, remote electric start, up to 18 hours at 25% load
- 52 dBA — quiet enough for a neighborhood
- 105.8 lbs — heavy, but it has wheels and a handle
- RV-ready 30-amp outlet, standard outlets, two USB ports
- 4.7 stars from 9,510 reviews
This is the one to buy if your plan is “fridge, lights, phones, and a CPAP.” It will not run central AC or a well pump plus a fridge at the same time.
If you need more: Westinghouse WGen11500DFc — $1,349 at Home Depot
- 14,500 peak / 11,500 running watts
- 9.5-gallon tank, up to 19 hours of runtime
- Under 5% THD — safe for electronics
- Built-in CO sensor that shuts the unit off
- Remote start, 50-amp outlet for a transfer switch
- 4.8 stars from 7,833 reviews
This covers a fridge plus a well pump, a second fridge, or a window AC. It is bigger, heavier, and burns more fuel — buy it only if your wattage math says you need it.
Also worth a look
- Westinghouse iGen5000DFcv — $849 at Home Depot. Same power as the iGen5000DFc but with a pull (recoil) start instead of remote electric start. Same engine, $150 less.
- Westinghouse iGen5000c — $899 at Home Depot. Same size, gasoline only. Skip it unless you are sure you will never want propane.
- Generac 10,000 / 8,000-watt portable — $1,049 at Lowe’s. Gasoline only, electric start, built-in CO sensor (COsense). A middle step between the two Westinghouse models.
- Westinghouse WGen11500TFc — $1,499 at Lowe’s. The tri-fuel version of the big Westinghouse — adds natural gas. Only useful if your home has a gas line.
Safety: the rules that keep people alive
Portable generators kill about 100 people a year in the U.S. from carbon monoxide (CO), according to the U.S. Consumer Product Safety Commission. CO has no smell and no color. Most deaths happen when someone runs a generator in a garage or too close to the house.
- Outside only, at least 20 feet from the house. Point the exhaust away from doors, windows, and vents. Never in a garage, basement, crawl space, or shed — even with the door open. During Hurricane Laura in 2020, 8 of 15 storm-related deaths in Louisiana were generator CO, and 5 of those were generators run in attached garages.
- Buy a model with a CO sensor. Look for UL 2201 certification. These models shut off automatically when CO builds up. The CPSC estimates UL 2201 models could have prevented nearly 100% of past generator CO deaths.
- Put battery-powered CO alarms in the house. One on each floor, near bedrooms. Test them monthly.
- Never backfeed. Do not plug a generator into a household outlet (usually a dryer outlet) to power the house. That sends electricity back into the grid and can kill utility workers. It is illegal and violates the National Electrical Code. Either run extension cords directly from the generator to each appliance, or have a licensed electrician install a transfer switch.
- Let it cool before refueling. Gasoline on a hot engine can ignite. Store fuel in approved containers, outside, away from the house.
- Ground it the way the manual says. For cord-and-plug use, most modern inverter generators do not need a separate ground rod. A transfer-switch install is where grounding matters — and that is an electrician’s job.
Hawaii notes: humidity, salt air, and fuel
- Salt air rusts steel. Wipe the unit down after use, keep it covered, and store it indoors (in a garage or shed) when it is not running. Spray exposed metal with a light corrosion inhibitor before hurricane season.
- Humidity and stale gas. Hawaii’s humidity makes gasoline go bad faster. Use fuel stabilizer in every can, and rotate your gasoline every few months. Propane does not go stale — another reason dual-fuel is the right call here.
- Fuel storage. Keep gasoline in approved containers, outside the living space, away from ignition sources. A 20-pound propane tank (the barbecue size) is easy to store and swap at any grocery or hardware store.
- Most Hawaii homes have no natural-gas line. Only 3.7% of Hawaii households heat with utility gas. If you are buying tri-fuel for the natural-gas option, confirm first that your home is actually on the Hawaii Gas pipeline (mostly urban Oahu). Otherwise, the third fuel is useless to you.
- After a hurricane, fuel may be hard to buy. Hawaii averaged 5.3 hours without power per customer in 2024 — short by mainland standards — but a hurricane is different. During Hurricane Lala in August 2026, over 40% of Hawaiian Electric customers lost power at the peak. Fill your tanks before the storm, not after.
- A battery power station is the quiet indoor option. For a CPAP overnight, a 300 watt-hour station is enough, and it makes no CO so it can run inside. It will not run an oxygen concentrator for long. Local shops like Battery Bill’s (Kalihi and Hilo) sell power stations and solar generators.
FAQ
Can I run my generator in the garage with the door open?
No. CO builds up fast even with the door open, and it seeps into the house through wall gaps and vents. Outside, at least 20 feet away — no exceptions.
Do I need a transfer switch?
Not for a portable generator if you run extension cords straight to the fridge and other appliances. But if you want the generator to power circuits in the house (lights, outlets), you need a transfer switch installed by a licensed electrician. It is required by law, and it is what keeps utility workers safe.
How much gasoline should I keep on hand?
For a 5,000-watt unit, plan on 5–10 gallons a day. Keep at least two days’ worth before hurricane season, use stabilizer, and rotate it. Or keep two 20-pound propane tanks — propane never goes stale.
Sources
- Home Depot — Westinghouse iGen5000DFc, $999, checked 12 Nov 2026: https://www.homedepot.com/p/Westinghouse-5-000-Watt-Dual-Fuel-Gas-and-Propane-Powered-Portable-Inverter-Generator-with-Remote-Electric-Start-LED-Data-Center-iGen5000DFc/318060927
- Home Depot — Westinghouse WGen11500DFc, $1,349, checked 12 Nov 2026: https://www.homedepot.com/p/Westinghouse-14-500-11-500-Watt-Remote-Electric-Start-Dual-Fuel-Gas-and-Propane-Portable-Generator-w-Low-THD-50A-Outlet-CO-Sensor-WGen11500DFc/334946375
- Home Depot — Westinghouse iGen5000DFcv, $849, checked 12 Nov 2026: https://www.homedepot.com/p/Westinghouse-5-000-Watt-Dual-Fuel-Gas-and-Propane-Powered-Portable-Inverter-Generator-with-Recoil-Start-LED-Data-Center-iGen5000DFcv/326302759
- Home Depot — Westinghouse iGen5000c, $899, checked 12 Nov 2026: https://www.homedepot.com/p/Westinghouse-5-000-Watt-Gas-Powered-Portable-Inverter-Generator-with-Remote-Electric-Start-LED-Data-Center-iGen5000c/318060859
- Lowe’s — Generac 10,000/8,000 W portable, $1,049, checked Nov 2026: https://www.lowes.com/pd/Generac-Gas-Powered-49-State-Electric-Start-w-COsense-10000-8000-Watt-Gasoline-Single-fuel-Portable-Generator/5019130951
- Lowe’s — Westinghouse WGen11500TFc, $1,499, checked Nov 2026: https://www.lowes.com/pd/Westinghouse-WGen11500TFc-Remote-Electric-Start-11500-Watt-Tri-Fuel-Gasoline-Propane-Natural-Gas-Portable-Generator/5015656283
- U.S. Consumer Product Safety Commission — portable generator CO deaths (~100/year; 749 deaths 2012–2022; UL 2201 effectiveness; Hurricane Laura and Ida cases)
- Lowe’s / Generac generator sizing worksheet — appliance running and starting watts
- Emergency Energy — “How to Power CPAP, Oxygen Concentrators & Medical Devices in an Outage” (2026): https://www.emergencyenergy.co/articles/emergency-power-medical-equipment/
- U.S. Energy Information Administration, Electric Power Annual, Table 11.3 — Hawaii 5.3 hours without power per customer, 2024
- American Community Survey 2024 — 3.7% of Hawaii households heat with utility gas
Disclaimer: This article is general information only, not insurance advice. Prices change — check the retailer’s site before you buy. For medical equipment, confirm your backup plan with the device maker or your doctor. For wiring, hire a licensed electrician.
Keep reading: Standby Generators: Generac vs. Kohler for Hawaii Homes · Does Homeowners Insurance Cover a Generator?