Sizing a generator comes down to four steps. Work through them before choosing a Westinghouse model.
1. Add up your running watts
List what you'll run at the same time and add up the running watts from each appliance's label. Rough figures for common RV loads:
- 13,500 BTU rooftop A/C: about 1,300–1,800 W running
- Microwave: 1,000–1,500 W
- Converter or charger: 300–800 W while charging
- Fridge on AC power, lights, water pump, TV: a few hundred watts combined
2. Allow for start-up surge
An A/C compressor briefly needs two to three times its running watts to start. That's why a generator's peak rating matters. Some owners add a soft-start kit to the A/C so a smaller generator can handle it.
3. Account for propane
A dual fuel generator makes about 10% less power on propane. For example, the iGen4000DFc makes 3,300 rated watts on gas and 2,970 on propane. Size for propane if that's what you'll mostly use. (More: how much wattage a dual fuel generator loses on propane.)
4. Match the outlet
A 30 amp RV plugs straight into a TT-30R outlet. The iGen2550c/DFc, iGen2800DFc, iGen4000 and iGen5000c models have one. The iGen1500c does not, so it suits small loads and charging rather than plugging in the whole RV. For a 50 amp RV, check the outlet on the generator's product page, or use the right adapter and manage your loads.
Sizing cheat sheet
| Your setup | Rated watts to look for | Westinghouse model |
|---|---|---|
| No A/C, charging and small appliances | 1,000 W | iGen1500c |
| Light loads, A/C only with a soft start | 1,900–2,200 W | iGen2550c, iGen2800DFc |
| One A/C plus everyday loads (30 amp) | 3,300 W+ | iGen4000 series, iGen5000c |
| Two A/Cs or a large rig | 5,000 W+ | WGen5300DFcv, iGen12000DFc |
See our picks in Best Westinghouse Generator for Your RV.