Quick Answer
Most travel trailers need a generator that produces between 2,000 and 4,000 running watts, depending on whether you plan to run an air conditioner. Many RV owners with a single 13,500 BTU air conditioner can use a 3,000-watt inverter generator, while a 3,500–4,000 watt generator provides more headroom for additional appliances, hot-weather operation, or heavier loads.
Choosing the right generator for your travel trailer doesn’t have to be complicated. The key is understanding how much power your RV actually needs, which appliances you’ll run at the same time, and whether you plan to use air conditioning. This guide walks you through everything step by step so you can choose the right generator with confidence.
Looking for specific generator recommendations? After determining the right generator size, read our Best Generator for Travel Trailers guide to compare the top models for different RV setups.
Understanding Generator Watts: Running vs. Starting
Every generator has two numbers that matter: running watts and starting watts. Running watts are the steady power your appliances need once they’re already operating. Starting watts are the extra burst of power certain appliances need for a second or two when they first switch on. For more RV electrical terms explained in plain English, see our RV Electrical Terms Explained guide.
Think about pushing a stalled shopping cart. Getting it moving from a dead stop takes a real shove. Once it’s rolling, keeping it moving takes much less effort. Electric motors and compressors work the same way—they need a strong initial burst of power to start, then settle into a lower, steady power draw.
Most RV appliances, such as LED lighting, phone chargers, televisions, and other small electronics, don’t require a large startup surge. However, appliances with electric motors or compressors—especially your roof-mounted air conditioner—can require significantly more power for a few seconds during startup.
Take a typical 13,500 BTU RV air conditioner. It may only use 1,500–2,000 running watts once it’s operating, but it can briefly require 2,800 watts or more while the compressor starts. A generator that’s large enough for the running load—but not the startup surge—may overload or fail to start the air conditioner.
Many first-time RV owners make the same mistake. They total the running watts of their appliances, buy a generator that matches that number, and then wonder why their air conditioner won’t start. Understanding the difference between running watts and starting watts is one of the most important parts of choosing the right generator.
Learn how these numbers affect air conditioners in our guide to Can a 3000 Watt Generator Run an RV Air Conditioner?
Pro Tip: Avoid sizing a generator right at its continuous running-watt limit. Leave some additional capacity for startup demands and appliances you may add later, and make sure the generator’s starting-watt rating can handle the largest startup surge.
Before comparing generator sizes, it’s important to understand these two terms because you’ll see them listed on every generator’s specifications.
What Are Running Watts?
Running watts are the steady amount of power an appliance needs after it’s already operating. This is the number you’ll usually see listed as Rated Watts or Continuous Watts on a generator’s specification sheet.
A coffee maker rated at 800 watts, for example, requires about 800 watts the entire time it’s brewing. Many everyday RV loads—including LED lights, battery chargers, televisions, and many newer 12-volt compressor refrigerators—operate with a relatively steady power draw once they’re running.
What Are Starting (Surge) Watts?
Starting watts—also called surge watts—are the extra burst of power a motor or compressor needs for a second or two when it first starts.
Starting watts can be significantly higher than running watts, especially for appliances with motors or compressors. The exact startup demand varies by appliance and model. Your RV air conditioner is the best example. Once it’s running, a typical 13,500 BTU unit may only need 1,500–2,000 watts. But when the compressor starts, it can briefly demand 2,800 watts or more.
If your generator can’t supply that short burst of power, the air conditioner may never start—even though the generator has enough power to keep it running afterward.
Why the Difference Matters for RV Appliances
This isn’t just a technical detail—it’s the difference between buying a generator that works and one that leaves you frustrated.
Picture arriving at your campsite on a hot afternoon. You connect your generator, switch on the air conditioner, and the generator immediately bogs down as the compressor tries to start. The lights flicker, the generator overloads, and the air conditioner shuts off.
That’s exactly what happens when a generator is sized using only running watts.
If you remember just one thing from this section, remember this:
Always choose a generator that can handle both the running watts and the starting watts of your largest appliance.
Calculate Your Exact Generator Size
Now that you understand the difference between running watts and starting watts, it’s time to calculate how much power your travel trailer actually needs.
Our free RV Generator Calculator helps you determine the right generator size in just a few seconds. Simply select your air conditioner size, estimate your other electrical loads, and indicate whether you’re using a soft start device or two generators in parallel. In just a few seconds, you’ll receive an estimate of both your running watt requirements and your starting watt requirements.
Once you know your recommended generator size, continue below to see the typical power requirements for common RV appliances and learn which generator size is right for your camping style.
RV Appliance Wattage Chart
Use the chart below to estimate the running watts of the appliances you expect to operate at the same time. Then verify that your generator can also handle the starting watts of your largest motor-driven appliance—usually the roof-mounted air conditioner. Combined with the RV Generator Calculator above, this chart will help you choose a generator with enough capacity for reliable operation without buying more generator than you need.
RV Appliance Wattage Chart
| Appliance | Running Watts | Starting Watts | Notes |
|---|---|---|---|
| RV Air Conditioner (13,500 BTU) | 1,500–2,000W | 2,800–3,500W | Starting watts can be reduced with a soft start device. |
| RV Air Conditioner (15,000 BTU) | 1,500–2,500W (commonly 1,800–2,000W) | 3,300–4,500W | Running watts vary by unit. Check the nameplate for the exact rating. |
| RV Refrigerator (Absorption) | 195–325W | Same as running | Traditional propane/120V RV refrigerator with no startup surge. |
| RV Refrigerator (12V Compressor) | ~180W | ~600W | Common in newer off-grid travel trailers. |
| Residential Refrigerator | 150–600W | 400–1,200W | Found in larger RVs with residential-style refrigerators. |
| Microwave | 750–1,500W | Same as running | No significant startup surge. |
| Coffee Maker | 800–1,200W | Same as running | Steady electrical load. |
| Electric Water Heater | 1,440–1,500W | Same as running | Electric element only—not propane mode. |
| Hair Dryer | 1,200–1,875W | Same as running | Varies considerably by model. |
| Electric Griddle / Skillet | 1,000–1,800W | Same as running | Thermostat cycles on and off. |
| Space Heater | 1,500W | Same as running | Standard portable electric heater. |
| TV / Laptop / Electronics | 50–300W | Same as running | Depends on device size and quantity. |
| LED Lights / USB Chargers | 20–100W | Same as running | Usually well under 100 watts combined. |
Source: U.S. Department of Energy — Appliance Energy Guides (energy.gov).
If you’d rather skip the calculations, the table below provides quick generator recommendations for the most common camping styles.
Recommended Generator Sizes at a Glance
| Camping Style | Electrical Service | Recommended Generator | Best For | Related Guide |
|---|---|---|---|---|
| Weekend Camper – No AC | 30 Amp | 2,000W Inverter | Lights, refrigerator, battery charging, small appliances | What Size Generator for a 30 Amp Travel Trailer? |
| Weekend Camper – Single 13.5K AC | 30 Amp | 3,000W Inverter | One rooftop AC plus normal RV appliances | Can a 3,000-Watt Generator Run an RV Air Conditioner? |
| Boondocking / Off-Grid | 30 Amp | 3,000–4,500W Inverter | Multiple appliances and extended generator use | Soft Start Systems for RV Air Conditioners |
| Large 50-Amp RV / Dual AC | 50 Amp | 5,000–8,000W or two paralleled 3,000–4,000W generators | Dual AC units and heavy electrical loads | Best Generator for a 50 Amp RV |
Generator Size for Running an RV Air Conditioner
Running watts alone don’t tell the whole story for air conditioners—and that’s where many RV owners make the wrong generator choice.
A typical 13,500 BTU RV air conditioner usually requires 1,500–2,000 running watts, but when the compressor first starts, it can briefly demand 2,800–3,500 starting watts. A 15,000 BTU unit generally requires 1,800–2,000 running watts, with startup surges reaching 3,300–4,500 watts.
That startup surge is why a basic 2,000-watt generator often isn’t enough. While it may be able to handle the air conditioner’s running load, it usually doesn’t have enough reserve capacity to supply the short burst of power needed when the compressor starts.
A soft start device can significantly reduce that startup surge by allowing the compressor to ramp up more gradually. In many cases, this makes it possible for a smaller generator to power an air conditioner that would otherwise require a much larger unit.
Even with a soft start installed, a 3,000–4,000 watt inverter generator can provide a good balance of startup capacity, everyday usability, and room for additional appliances for many travel trailer owners. It offers enough headroom to run a single air conditioner while still powering essentials like a refrigerator, battery charger, lights, or a microwave without constantly operating at its limit.
Choosing the Right Generator Size for Your Camping Style
Choosing the right generator isn’t just about trailer size—it’s also about how you camp. A weekend camper with basic electrical needs has very different power requirements than a full-time RVer running multiple air conditioners. The examples below will help you match the right generator size to the way you actually use your travel trailer, making it easier to choose a generator that fits both your camping style and your electrical needs.
Before running a generator at your campsite, review our Generator Safety Checklist for safe placement, fueling, ventilation, and operation.
Weekend Campers & Occasional RV Users
If you camp a few weekends each year and rarely use your air conditioner, a 2,000-watt inverter generator is often all you need. It’s quiet, lightweight, fuel-efficient, and easily handles battery charging, LED lights, televisions, phone chargers, and small kitchen appliances.
The biggest limitation is air conditioning. A 2,000-watt generator is rarely large enough to start and run a typical RV air conditioner. If you plan to use your air conditioner—even occasionally—a 3,000-watt inverter generator is usually the better long-term investment. It provides the extra startup capacity needed for a 13,500 BTU air conditioner while still remaining portable and campground friendly.
Boondockers & Off-Grid Campers
If you regularly camp without hookups, you’ll likely run more appliances for longer periods of time. In addition to powering your air conditioner, you may also be charging batteries, running a microwave, making coffee, or using other appliances throughout the day.
For most boondockers, a 3,000 to 4,500-watt inverter generator offers the best balance of power, fuel efficiency, and flexibility. It provides enough capacity to run a single air conditioner along with several everyday appliances without constantly operating near its maximum output.
Installing a soft start device can reduce your air conditioner’s startup surge, which may allow a properly sized 3,000-watt generator to start and run the air conditioner more reliably.
One mistake many off-grid campers make is underestimating how much fuel they’ll need for multi-day trips. Choosing an efficient inverter generator and planning your fuel supply are just as important as selecting the right wattage.
Full-Time RVers & Large 50-Amp Trailers
If you own a large fifth wheel or 50-amp travel trailer, especially one with two air conditioners, your electrical needs are in a different category.
For large 50-amp RVs with two air conditioners or heavier electrical loads, a 5,000 to 8,000-watt generator—or two inverter generators connected in parallel—can provide the additional capacity needed. Trying to power two air conditioners with a single 4,500-watt generator usually leads to frustration, limited flexibility, and frequent overloads.
If this describes your setup, be sure to read our detailed guides on 50-amp RV generators, running multiple air conditioners, and RV soft start systems for more advanced sizing recommendations.
Quick Reference: See the Recommended Generator Sizes at a Glance table above for a side-by-side comparison of camping styles, RV electrical service, and our recommended generator sizes.
Final Recommendation
Choosing the right generator doesn’t have to be complicated. By now, you have everything you need to size a generator with confidence. There’s no single “best” generator for every travel trailer owner—the right choice depends on your camping style, the appliances you plan to use, and how much electrical power you actually need.
If you camp a few weekends each year and rarely use air conditioning, a 2,000-watt inverter generator is often the perfect fit. It provides reliable power for your essentials without adding unnecessary weight, noise, or fuel consumption.
For many travel trailer owners with a single 13,500 BTU air conditioner, a 3,000-watt inverter generator can provide a good balance of portability and power when loads are managed carefully. If you want more headroom for additional appliances, hot-weather operation, or a larger 15,000 BTU air conditioner, a 3,500–4,000 watt generator is often the better choice.
If you own a larger trailer, have a 15,000 BTU air conditioner, or regularly run multiple high-demand appliances, stepping up to a 4,000–4,500 watt generator provides additional flexibility and valuable reserve capacity.
If you’re still unsure, use the RV Generator Calculator and RV Appliance Wattage Chart above. Taking a few minutes to estimate your actual power requirements is the best way to choose the right generator with confidence.
The best generator isn’t necessarily the biggest one—it’s the one that matches your travel trailer, your electrical needs, and the way you camp. Choosing the right size today will provide quieter, more reliable camping for years to come.
