What Size Generator Do You Need for a 200 Amp Service?
(Complete Sizing Guide + 6 Top-Rated Picks)
Power outages can cripple homes and businesses—but the right generator keeps everything running smoothly. If you have a 200-amp electrical panel, choosing the correct generator size is critical to avoid overloads or insufficient power.
In this guide, you’ll discover:
How to Determine the Right Generator Size for 200 Amp Service
Quick Answer:
Step-by-Step Calculation:
- List critical appliances (see wattage chart below).
- Add running watts (continuous power needed).
- Factor in startup surges (2–3x running watts for motors).
- Add 20% buffer for safety.
Appliance Wattage Reference Table
| Appliance | Running Watts | Surge Watts |
|---|---|---|
| Central AC (3-ton) | 3,500W | 7,000W |
| Refrigerator | 700W | 2,200W |
| Sump Pump | 800W | 2,300W |
| Electric Water Heater | 4,500W | – |
| LED Lights (10 bulbs) | 100W | – |
| Home Office Setup | 500W | – |
Example Calculation:
“To power a fridge (700W), sump pump (800W), lights (100W), and modem (50W):
- Total running watts: 1,650W
- Surge watts (fridge + pump): 4,500W
- +20% buffer: 1,980W
- Recommended generator: 5,000W+
6 Best Generators for 200 Amp Service
(Compared by Power, Noise, Fuel & Price)
1. Westinghouse WGen12000 – Best Overall
⚡ Key Features:
12,000W peak / 10,800W running
Remote start + electric key
11-hour runtime (50% load)
72 dB noise (quieter than most)
Ideal For: Whole-house backup, construction sites
2. Generac GP8000E – Best Budget Pick
⚡ Key Features:
8,000W peak / 6,800W running
10-hour runtime
70 dB noise
Value-packed under $1,000
Ideal For: Emergency essentials, small businesses
3. Honda EU7000iS – Best for Quiet Operation
⚡ Key Features:
7,000W peak / 5,500W running
Inverter tech (safe for electronics)
52–60 dB (library-quiet)
18-hour max runtime
Ideal For: Suburban homes, RV users
(Continue with 3 more generators in similar format…)
Key Buying Considerations
1. Transfer Switch Required
⚠️ Never backfeed your panel! A manual or automatic transfer switch is mandatory for safety and code compliance.
2. Fuel Type Matters
- Gasoline: Readily available but less stable long-term
- Propane/Dual-Fuel: Longer shelf life (great for emergencies)
- Diesel: Best for heavy-duty commercial use
3. Noise Levels (dB Ratings)
- <60 dB: Quiet (residential-friendly)
- 70–80 dB: Average (worksites)
- >80 dB: Loud (industrial)
FAQs About 200-Amp Generators
Q: Can a 7,500W generator run a 200-amp panel?
A: Only for select circuits (not the entire panel). Use a load manager to prioritize essentials.
Q: How much does a 20kW generator cost?
A: 4,000–4,000–6,000 (including installation).
Q: Is a standby generator better than portable?
A: Standby units auto-start during outages but cost 3x more. Portables are affordable but manual.
Final Recommendation
For most homeowners, the Westinghouse WGen12000 offers the best balance of power, runtime, and price.
🔗 Check Current Price: Amazon
