What Size Generator to Run an RV Air Conditioner? RV Guides, December 18, 2024December 21, 2024 When you’re out on the road in your RV, few things are as essential for comfort as your air conditioner. Whether you’re escaping the summer heat or camping in a remote location, staying cool is a priority—but running an RV air conditioner requires a reliable power source, especially when shore power isn’t available. That’s where a generator comes in. In this guide, we will walk you through everything you need to know about selecting the perfect generator for your RV air conditioner. From understanding wattage requirements to exploring common generator sizes and popular models, we’ll help you make an informed decision so you can enjoy your travels in comfort. Common Generator Sizes for RV Air Conditioners Generators for Smaller Air Conditioners (2,000–3,000 Watts) Smaller RV air conditioners, such as 9,000 or 11,000 BTU units, require less power to start and run. For these models, a generator in the range of 2,000–3,000 watts is usually sufficient. These generators are lightweight, portable, and fuel-efficient, making them ideal for campers who prioritize mobility and ease of use. For example, a 2,000-watt generator can typically handle the starting surge of a smaller air conditioner while still leaving enough capacity for a few additional appliances, like LED lights, a small fan, or a phone charger. However, if you plan to use multiple devices simultaneously, it’s important to confirm their combined wattage does not exceed the generator’s capacity. Smaller generators are a popular choice for minimalist setups or smaller RVs where the cooling demand is lower. They are also quieter compared to larger models, which is a bonus in campgrounds where noise restrictions may apply. Generators for Larger Air Conditioners (3,500+ Watts) For standard RV air conditioners, such as 13,500 or 15,000 BTU units, you’ll need a generator with a capacity of at least 3,500 watts. These air conditioners have higher starting and running wattage requirements, and a generator in this range ensures sufficient power for the air conditioner as well as additional appliances like a refrigerator, microwave, or coffee maker. A 3,500-watt generator can comfortably handle the power surge required to start the air conditioner and maintain a steady output for its running wattage. This size generator is also versatile enough for larger RV setups or situations where multiple high-wattage devices may be used simultaneously. For RVers traveling to hot climates or who rely heavily on air conditioning, a 3,500+ watt generator offers peace of mind and flexibility. While these generators tend to be heavier and bulkier, their increased capacity ensures reliable power under demanding conditions. Why You Need a Generator for an RV Air Conditioner? Understanding RV Air Conditioner Power Requirements RV air conditioners are one of the most power-intensive appliances in your vehicle. These units, typically rated in BTUs (British Thermal Units), require a substantial amount of electricity to start and run effectively. For instance, a standard 13,500 BTU RV air conditioner might need around 2,800-3,000 watts to start and about 1,500-2,000 watts to continue running. Larger units, such as 15,000 BTU models, demand even more power. The initial surge of electricity—known as starting watts—is necessary to get the air conditioner’s compressor running. This surge is significantly higher than the running wattage required to keep the unit operational. Without an adequate power supply, the air conditioner may not start, or worse, the undersized power source could overheat or get damaged. When a Generator is Essential There are several scenarios where a generator becomes a critical tool for running your RV air conditioner. One common situation is boondocking, where you park in remote areas without access to shore power. In these off-grid camping experiences, a generator serves as your main source of electricity, providing the power needed to maintain comfort in hot weather. Even at campgrounds, not all sites offer electrical hookups. If you’re camping during peak seasons or in areas with limited amenities, having a generator ensures that your air conditioner, along with other essential appliances, can function seamlessly. Moreover, in emergencies where power outages occur, a generator can keep you cool and comfortable while protecting sensitive electronics inside your RV. Benefits of Having a Properly Sized Generator Choosing the right-sized generator brings numerous benefits. First and foremost, a properly sized generator ensures that your air conditioner and other appliances can run efficiently without interruptions. This eliminates the frustration of tripped breakers or failed startups due to insufficient power. Additionally, a well-matched generator improves fuel efficiency. Oversized generators may waste fuel, while undersized ones can strain under the load, leading to higher fuel consumption and potential mechanical failures. A correctly sized generator strikes a balance, providing reliable power while maximizing runtime on a single tank of fuel. Finally, using the right generator enhances the longevity of both your air conditioner and the generator itself. Consistent, stable power reduces wear and tear on electrical components, ensuring that your equipment lasts longer and performs better over time. With a properly sized generator, you can enjoy your RV adventures with peace of mind, knowing you have a dependable power source for your cooling needs. Understanding RV Air Conditioner Power Requirements What Are BTU Ratings and Why Do They Matter? BTU, or British Thermal Units, is a standard measurement used to define the cooling capacity of an air conditioner. The higher the BTU rating, the more powerful the air conditioner, which means it can cool a larger space or handle higher temperatures more effectively. For RVs, air conditioners typically range from 5,000 BTUs for smaller units to 15,000 BTUs for large, powerful models. In the context of RVs, understanding the BTU rating is crucial because it determines the power requirements of the air conditioner. A higher BTU unit will require more electricity to start and run, while smaller BTU units are less demanding but may struggle to cool a larger RV effectively. Choosing the right air conditioner based on your RV size and climate needs is the first step toward determining the appropriate generator size. Typical Power Ratings of RV Air Conditioners RV air conditioners typically fall into two main categories based on their BTU ratings: 13,500 BTU units and 15,000 BTU units. A 13,500 BTU air conditioner is considered the standard for most RVs and requires approximately 2,800–3,000 watts to start and around 1,500–2,000 watts to run. These units strike a good balance between cooling power and energy efficiency, making them a popular choice for medium-sized RVs. For larger RVs or those traveling in extremely hot climates, a 15,000 BTU air conditioner may be necessary. These units can require up to 3,500 watts to start and around 2,000–2,500 watts to run. While they provide greater cooling capacity, their higher energy demands must be taken into account when selecting a generator. Smaller RV air conditioners, such as 9,000 or 11,000 BTU models, require less power, making them compatible with smaller, portable generators. Starting Watts vs. Running Watts: Why the Difference Matters When determining generator size, it’s critical to understand the difference between starting watts and running watts. Starting watts, also called surge watts, refer to the initial burst of power required to start an appliance, particularly ones with motors or compressors, like an air conditioner. This surge only lasts for a few seconds but can be up to 2–3 times higher than the running watts. Running watts, on the other hand, represent the continuous power needed to keep the appliance operating. For example, a 13,500 BTU air conditioner might require 3,000 watts to start but only 1,500 watts to run. Failing to account for the higher starting wattage can lead to an undersized generator that struggles to power your air conditioner, resulting in failed startups or overloading the generator. Generator Sizing Basics What Is Wattage and Why Does It Matter? Wattage is a measure of electrical power and indicates how much energy a device or appliance consumes when in use. For generators, wattage capacity determines how many appliances it can power simultaneously and whether it can handle devices with high energy demands, such as an RV air conditioner. Choosing a generator with the correct wattage is crucial for ensuring a stable and reliable power supply. When it comes to RV air conditioners, wattage is particularly important because these devices require both high starting power (to get the compressor running) and steady running power. If your generator doesn’t have enough wattage to support your air conditioner and other devices, it may fail to start or cause interruptions during use. Key Terms: Surge Watts and Continuous Watts Understanding the two types of wattage—surge watts and continuous watts—is key to sizing a generator properly. Surge Watts (Starting Watts): This is the extra power a generator can deliver temporarily to start appliances with motors or compressors, such as air conditioners. This surge typically lasts for a few seconds but is critical to get the appliance up and running. For instance, a 13,500 BTU air conditioner may need 2,800–3,000 surge watts to start. If the generator cannot provide this power, the air conditioner will fail to start, and the generator may trip or shut down. Continuous Watts (Running Watts): This is the amount of power required to keep an appliance running steadily after it has started. It is typically lower than the surge wattage. For example, the same 13,500 BTU air conditioner might require only 1,500–2,000 watts to run once it has started. Generators are rated based on their continuous wattage capacity, so it’s important to ensure that the running power of all your devices combined does not exceed this limit. By understanding and balancing surge and continuous wattage needs, you can ensure your generator operates efficiently and without overloading. The Risks of Using an Undersized Generator Using a generator that is too small for your RV air conditioner and other appliances can lead to several problems, both for your equipment and for the generator itself. One major risk is overheating, as an undersized generator will struggle to meet the demand and may run at maximum capacity for extended periods. This can lead to mechanical failures, reduced efficiency, and permanent damage to the generator. Another risk is damage to appliances. If the generator cannot provide a stable power supply, sensitive appliances like air conditioners may experience voltage drops or surges. This instability can harm electrical components, reduce the lifespan of your appliances, and result in costly repairs. Additionally, an undersized generator may frequently trip or shut down, leaving you without power when you need it most. This can be particularly frustrating in hot weather when you rely on your air conditioner for comfort. To avoid these risks, it’s essential to calculate your total power needs accurately and choose a generator that provides sufficient wattage for both starting and running your RV air conditioner. How to Calculate the Right Generator Size? Step 1: Find Your RV Air Conditioner’s Starting and Running Wattage The first step in determining the right generator size is to understand the power requirements of your RV air conditioner. These requirements are typically listed in the unit’s manual or on a label attached to the appliance. You will need two specific values: the starting wattage (also called surge wattage) and the running wattage (continuous wattage). For example, a 13,500 BTU air conditioner may require around 2,800–3,000 watts to start and 1,500–2,000 watts to run. If you cannot locate the exact wattage, you can use the BTU rating as a general guide. Remember, larger units, such as a 15,000 BTU air conditioner, will require more power—up to 3,500 watts to start and 2,500 watts to run. Having these numbers will give you a clear starting point for your generator selection. Step 2: Account for Additional Devices and Appliances Next, consider other appliances or devices you will run simultaneously with your air conditioner. Common appliances in an RV include refrigerators, microwaves, TVs, lights, and charging devices. Each of these items requires its own wattage, which will add to the total demand on your generator. For example: Refrigerator: 600 watts running, 1,200 watts starting. Microwave: 1,000–1,500 watts. Lights: 100–300 watts, depending on how many are in use. Phone/Device Chargers: 20–50 watts each. Add up the running wattage of all the devices you plan to use at the same time. Then, include the starting wattage for any appliance that may require a power surge. Ensure your generator can handle the combined wattage of your air conditioner and other appliances during their peak demand. Step 3: Add a Safety Margin To ensure reliable operation and prevent overloading your generator, it’s essential to include a safety margin. A good rule of thumb is to add 20–30% extra capacity to the total wattage. This margin accounts for unforeseen power needs, fluctuations, or the addition of new appliances in the future. For example, if your RV air conditioner requires 3,000 watts to start and your other devices add up to 1,000 watts, your total wattage would be 4,000 watts. Adding a 20–30% safety margin means you should look for a generator rated at least 4,800–5,200 watts. This extra capacity helps ensure stable performance, reduces strain on the generator, and provides flexibility for additional power needs. Putting It All Together By following these steps, you can calculate the right generator size for your RV: Identify the starting and running wattage of your air conditioner. Add the wattage of any other appliances you’ll run simultaneously. Include a 20–30% safety margin to determine the total wattage your generator needs to support. Enjoyed this guide of what size generator to run an RV air conditioner? Then be sured to check out our other RV guides. Best 12 Volt RV Battery Best Cell Phone Signal Booster for RV Best Generator for 30 Amp RV Best Generator for 50 Amp RV Best 3000 Watt Inverter Generator for RV Best Dual Fuel Inverter Generator for RV RV Guides RV