For most homes, you need a 5,000 to 7,500 watt portable generator for essential circuits (fridge, lights, sump pump, WiFi), or a 15,000+ watt standby generator for whole-home backup including central AC.
Use the calculator below to get an exact recommendation based on the appliances you need to power, or scan the quick reference table for common scenarios.
Backing up your home for outages? Read what size backup generator you need for a whole house for sizing tables by home size and appliance load.
Select your use case, check the appliances you need to power, and get an instant recommendation.
Top picks for the most popular generator use cases, with specs and direct links to check current pricing.
5,000–22,000W
For whole-house backup including central air conditioning, you need a 17,000 to 22,000W standby generator. For whole-house backup without central AC, a 12,000W large portable handles it.
2,000–3,500W
A 2,000–3,500W portable inverter generator is the right size for camping. It runs lights, phone chargers, a portable fridge, a coffee maker, and a small TV quietly enough for campground use.
5,000–7,500W
A 5,000–7,500W portable generator covers essential home circuits during a power outage. That includes your refrigerator, freezer, lights, sump pump, WiFi router, phone chargers, and one window AC unit.
10,000–12,000W
A 10,000–12,000W portable generator powers nearly every circuit in your house except central air conditioning. That covers your refrigerator, freezer, sump pump, well pump, window AC, space heater, microwave, lights, and all your electronics running simultaneously.
15,000–22,000W+
A 15,000–22,000W+ standby generator is what you need for whole-home backup including central AC. These permanently installed units start automatically within seconds of a power outage and run on natural gas or propane, so there is no refueling.
3,500–5,000W
A 3,500–5,000W generator is the right size for RV camping with air conditioning. An RV air conditioner draws 3,000W starting and 1,800W running, leaving enough headroom on a 3,500W+ unit for your RV fridge, TV, lights, and phone chargers.
5,000–7,500W
A 5,000–7,500W dual fuel generator is the best choice for power outage preparedness. It keeps your refrigerator, freezer, sump pump, lights, WiFi, and phone chargers running through any storm.
5,000–7,500W
A 5,000–7,500W portable generator handles most construction power tools. A circular saw (2,400W starting), air compressor (4,500W starting), and electric drill (900W starting) all run comfortably on a 7,500W unit.
2,000–3,500W
Yes, even a small 2,000W portable generator can run a full-size refrigerator. A typical fridge draws about 150W running and 1,200W on startup.
5,000–7,500W
A 5,000–7,500W generator runs most window air conditioners reliably. A 5,000 BTU unit draws about 500W running and 1,500W starting, while a 12,000 BTU unit draws up to 1,500W running and 3,000W starting.
2,000–7,500W
Yes, a generator rated 2,000W or higher can run a sump pump. A typical 1/3 HP sump pump draws about 800W running and 1,500–2,000W on startup.
5,000–7,500W
Yes, a generator can run an electric space heater. A standard 1,500W space heater is a resistive load with no startup surge, so it draws a flat 1,500W from the moment you turn it on.
2,000–5,500W
Under $500, you can get a quality 2,000–5,500W generator that handles camping, tailgating, or basic home backup. The sweet spot is a budget inverter generator around $350 for portable use, or a dual fuel conventional generator around $450 for home backup with more power and fuel flexibility.
2,000–7,500W
The $500–1,000 range is the sweet spot for most generator buyers. You get dual fuel capability, electric start, CO safety shutoff, and transfer switch outlets in the 5,000–7,500W range — enough to power essential home circuits plus a window AC during an outage.
5,000–7,500W
A food truck needs a 5,000–7,500W generator to run a commercial refrigerator, griddle, fryer, lights, POS system, and exhaust fan simultaneously. Dual fuel models are preferred because propane is cleaner, quieter-smelling, and often required by food service regulations and venue noise ordinances.
3,500–7,500W
For RV living and travel, you need a 3,500W inverter generator at minimum for a single AC unit, or a 5,000–7,500W model to run the AC plus a microwave, hair dryer, or multiple appliances simultaneously. Inverter generators are strongly preferred for RVs because they produce clean power for sensitive electronics and run quietly.
Skip the calculator. Find your scenario and get the answer.
| If You Need To Power... | You Need At Least... | Generator Type |
|---|---|---|
| Phone, laptop, lights, small devices | 2,000W | Portable Inverter |
| Fridge + lights + sump pump + WiFi | 3,500–5,000W | Portable |
| Fridge + window AC + essentials | 5,000–7,500W | Portable |
| Most home appliances (no central AC) | 7,500–10,000W | Portable |
| Full home backup with central AC | 15,000–22,000W+ | Standby |
| RV with AC | 3,500–5,000W | Portable Inverter |
| Jobsite power tools | 5,000–7,500W | Portable |
Generator noise levels compared to everyday sounds. Inverter generators run as quiet as a conversation, while large portables approach lawn mower territory.
A transfer switch safely connects your generator to your home panel. Use our calculator to find the right size.
Solar panels produce silent, free power with zero fuel cost. For off-grid cabins, RVs, and backup power, solar is often cheaper over 5 years than a generator.
A 2,000 sq ft house typically needs a 7,500W generator for essential circuits (fridge, lights, sump pump, window AC, WiFi) or a 15,000W+ standby generator for whole-home backup with central AC. Square footage alone does not determine generator size. What matters is the total wattage of the appliances you want to power simultaneously. A 2,000 sq ft home with central AC needs 15,000W+, but the same house running only essentials needs 5,000-7,500W.
A refrigerator needs just 150 running watts but draws up to 1,200 watts on startup when the compressor kicks in. A 2,000W inverter generator handles a fridge with plenty of room for lights, phone chargers, and a WiFi router. If you also want a freezer and sump pump, step up to a 5,000W unit. The DuroMax XP5500HX handles the fridge startup surge plus 4,000W of additional appliances, and dual fuel capability means you can switch to propane when gasoline runs out during extended outages.
For RV camping with air conditioning, you need a 3,500-5,000W generator. An RV air conditioner draws 3,000W on startup and 1,800W running, which is the biggest power draw in most RVs. The Champion 3500W Inverter is purpose-built for RV use with a TT-30R RV outlet, quiet 58 dB operation that meets most campground noise rules, and CO Shield safety shutoff. At 58 lbs, it is light enough for one person to load. It produces clean inverter power safe for all RV electronics.
Most homes need a 5,000–7,500W portable generator for essentials (fridge, lights, sump pump, WiFi) or a 15,000–22,000W+ standby generator for whole-home backup with central AC.
A refrigerator needs about 150 running watts but up to 1,200 starting watts. A 2,000W generator handles a fridge easily with room to spare for lights and phone chargers.
3,500–5,000W covers most RVs including AC. Get an inverter generator for clean power that protects sensitive electronics like TVs and laptops.
A 10,000 BTU window AC needs about 1,200 running watts and 3,600 starting watts. A 5,000W generator handles one window AC unit plus other essentials.
Running watts measure continuous power draw during normal operation. Starting watts measure the brief surge when a motor kicks on, typically 2–3x higher than running watts. Your generator must handle the highest starting surge on top of everything else running.
Central AC needs 10,500+ starting watts. You need a standby generator (15,000W+) or a very large portable (12,000W+). Most standard portable generators can't handle central AC.
Most portable generators run 8–12 hours at 50% load on a full tank. Inverter generators with eco-mode can stretch to 10–18 hours. Larger tanks and lower loads mean longer runtime.
Inverter generators produce cleaner power (safe for electronics), run quieter (48–58 dB vs 70+ dB), weigh less, and use less fuel. They cost more and usually max out around 7,000W. Conventional generators are louder but cheaper and available in higher wattages.
5,000–7,500W for basic power tools like drills and circular saws. 10,000W+ if running multiple tools simultaneously or heavy equipment like an air compressor.
Yes, if connecting a generator to your home's electrical panel. A transfer switch prevents backfeeding into power lines, which is illegal and dangerous. Professional installation typically costs $200–$500.