Choosing the Right Portable Generator Size
Portable generators are the most versatile power solution available — they can work at a campsite one weekend and power your home during a storm the next. The key is matching the generator to your primary use case, then confirming it can handle any secondary uses.
The single biggest sizing factor is whether you need to run an air conditioner. AC units have high startup surges that make them the most demanding common load. If you need to run an RV AC or window AC unit, your generator selection jumps from the 1,000–2,000 watt range to 3,500+ watts.
Inverter Generators: When the Extra Cost Is Worth It
Inverter technology in portable generators does one thing conventional generators can't: produce “clean” AC power with stable voltage and frequency, similar to what comes from your wall outlet. This matters for:
- Sensitive electronics: Laptops, smartphones, CPAP machines, and smart TVs are all sensitive to power quality. Irregular power from conventional generators can cause flickering, data corruption, or component damage over time.
- Quiet operation: Inverter generators run at variable speed — throttling down when demand is low. This makes them 15–30 dB quieter than comparable conventional generators and dramatically improves fuel economy.
- Parallel capability: Many inverter generators can be linked to double capacity, giving you flexibility conventional generators lack.
The downside: inverter generators cost 30–70% more per watt than conventional generators. For high-wattage job site use where noise and electronics quality are less of a concern, conventional generators offer better value. For camping, RVs, and home electronics backup, the inverter premium is well worth it.
Running Watts vs. Rated Watts on Portable Generators
When shopping for a portable generator, you'll see both “running watts” and “starting watts” (or “surge watts”) in the specifications. Running watts is the continuous capacity the generator can sustain. Starting watts is the brief peak the generator can handle for 1–2 seconds.
For example, a generator marketed as “5,500W / 6,875W surge” can run 5,500 watts continuously but can absorb a 6,875-watt startup burst from a motor. When sizing, match your total running load to the generator's running watts, and make sure your largest single motor surge doesn't exceed the generator's starting watts.
Soft-Start Kits: Run More AC on Less Generator
A soft-start kit (also called a hard-start kit or EasyStart by MicroAir) is a small electronic device installed on an AC unit's compressor that gradually ramps up motor speed instead of starting at full voltage. This reduces the startup surge of an AC unit by 50–70%.
With a soft-start kit, an RV AC unit that normally requires 3,500 watts to start can often be started on a 2,000–2,200 watt inverter generator. This is a $150–$250 investment that expands what your existing generator can power dramatically. It also extends compressor life by reducing mechanical stress at startup.
Portable Generator Maintenance Essentials
A generator that won't start during an emergency is worse than useless — it's false security. Prevent this with a simple maintenance routine:
- Monthly exercise run: Start your generator under load for 30 minutes every month. This keeps the carburetor clean, lubricates seals, and tests the electrical system.
- Fresh fuel: Stale gasoline is the #1 cause of generator starting problems. Add STA-BIL fuel stabilizer if you might store the generator more than 30 days without running it.
- Oil changes: Change oil after the first 20 hours of use (break-in), then every 100 hours or annually. Most small engines use SAE 30 or 10W-30.
- Air filter: Clean or replace annually or every 100 hours, more often in dusty environments.
- Spark plug: Replace every 200 hours or at first sign of hard starting.
Need to plan for a complete home backup? See our backup generator size calculator for emergency planning guidance.