Guide to Choosing the Most Optimal Generator Size for RV AC

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

Last Updated On

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When it comes to RV life, staying cool is key, but figuring out the right generator for your AC can feel like a monumental task.

As someone who's spent plenty of time tinkering with RV systems, I get how tricky it can be. You want enough power for comfort without going overboard.

In this guide, I'll explain how to pick the perfect generator size for your RV's air conditioning, ensuring you stay comfortably cool as you embrace the freedom of the open road.

Let’s get started!

Key Takeaways

  • To choose the right generator size for your RV AC, assess and calculate the starting wattage requirement of the AC and of all the appliances you will use at a given time. 
  • The starting wattage is the instantaneous power the ACs need when starting up which is much higher than the steady state or continuous power requirement. Generators must be sized in accordance with the starting wattage.
  • The amp rating of your RV and the RV class is a good starting point for determining the size of the generator.

My Recommendations For Sizing a Generator

Finding the right generator size for running RV AC units can really make a difference in your road trips.

I've compiled some easy tips to help you pick the right one.

Whether you're hitting the road for the first time or are a seasoned traveler, it's all about ensuring your comfort with the ideal generator size.

Here are several factors you need to know:

Assess Total Wattage Needed

Picking the right generator size reminds me of planning a trip – you've got to know what you need.

It's crucial to balance your RV's AC needs with the power requirements of other RV appliances like refrigerators and microwave ovens.

To properly assess the total wattage, start by listing the wattage requirements of each appliance, including both their running and starting wattage.

This information is typically found on the appliance labels or in their manuals.

It's like just packing a swimsuit for a mountain trip – you're unprepared.

I've seen clients overlook the wattage for something as power-hungry as a 15000 BTU air conditioner, and trust me, it's not a situation you'd want to find yourself in.

TL;DR: You must take the wattage of not just the AC's but also that of other appliances into consideration.

Consider the AC's Demand

When it comes to powering air conditioning units in an RV, especially those rigs sporting 2 AC units, the power demand is something to really ponder.

These units don’t just require more power; they have specific appetites for energy.

I always remind people about two important things: the starting watts – how much power it needs to kick things off – and the running watts, which refer to their energy consumption as you operate the AC.[1]

For example, a typical RV AC unit might require about 2800 starting watts and then stabilize at around 1800 running watts.

This means the generator must be capable of handling this initial surge without tripping and then sustain the lower power level for ongoing operation.

Choosing a generator isn't just about meeting these demands; it's about ensuring enough juice to comfortably power up without overloading or shortchanging your system.

RV AC Size BTU

Starting Wattage

Running Wattage

11,000 BTU

1,600 watts

1,010 watts

13,500 BTU

2,800 watts

1,800 watts

15,000 BTU

3,300 watts

2,000 watts

TL;DR: Consider not just the running wattage, but also the surge or the starting wattage of the air conditioner.

Generator Type and Fuel Source

Navigating the choice between gas, solar, or electric generators often feels like weighing different travel routes – each has unique advantages depending on the journey.

From my experience, solar generators are a great fit for those leisurely trips where energy demands are on the lower side.

Solar panels are quieter and more eco-friendly, specifically fuel efficient, but require sunny conditions to be effective.

On the other hand, gas generators are the go-to for higher wattage needs.

They pack more power and are reliable for those who don't mind a bit of noise and need that extra energy punch.

If you opt for electric ones, these generators work by using electricity.

You may need to buy portable power stations if you need extra power or more energy to run AC and other equipment in your RV.

In some cases, I’ve come across customers trying to use shore power generators.

These are different from RV generators as they are made specifically for water vehicles, so it’s not something I recommend.

Here’s a cheat sheet to easily check which generator type suits your lifestyle best:

Generator Type

Cost

Availability

Best Use Case

Solar Generators

Moderate to High

Widely Available

Low energy demands, eco-friendly settings

Gas Generators

Low to Moderate

Very Common

High wattage needs, versatility

Electric Generators (Portable Power Stations)

High

Common

Situations requiring clean, quiet power

Shore Power Generators

Varies

Specialized

Specifically for water vehicles, not ideal for RVs

TL;DR: Choose the generator based on fuel type most readily available to you and depending upon your use case.

Voltage and Wattage Specifications

When choosing a generator, matching it to the voltage and wattage specs of the camper van is like finding the right key for a lock – it has to be precise.

It's vital for not just running the AC and other appliances smoothly but also for the safety of the entire system.

Overloading can be a real risk if the match isn't spot on.

I always double-check these specifications to ensure that everything from the common appliances I run to the lights can operate without a hitch, keeping the journey safe and comfortable.

To determine the voltage and wattage specifications of your RV, you can start by consulting the owner's manual, which typically lists these details.

If the manual isn’t available, look for a label or plate on each appliance, usually located at the back or bottom, that indicates its power requirements.

For a more comprehensive understanding, consider using a wattage meter that can measure the actual power consumption of each appliance when it's running.

This method can give you a more accurate picture, especially if you've added new appliances or the existing ones have aged, as their power needs might have changed over time.

TL;DR: Make sure the voltage rating of the generator is same as that of your RV and the appliances that you use.

Installation Considerations

Installing the right size generator is a bit like fitting a new piece into a puzzle – it has to integrate seamlessly with the camper or motorhome's electrical system.

My experiences with different RV setups taught me that it's not just about compatibility but also how easily the generator can connect to the existing system.

The smoother this integration, the less hassle there is down the road. Connecting all components harmoniously is key to a stress-free adventure.

Here’s what I usually do to ensure that my new RV generator is compatible with all of my appliances:

  1. 1
    First, I check the RV's electrical system – whether it's a 30-amp or a 50-amp system, as this dictates the kind of generator I can use. This information can be found in the RV's manual or on a label near the RV's power cord.
  2. 2
    Next, consider the plug types and the power outlets on your generator. They need to match with what your RV requires. If they don’t, you might need an adapter. It’s also important to look at the generator’s output in terms of voltage and wattage to ensure it aligns with your RV’s electrical needs.

ACLAB Note:

For a more thorough compatibility check, consulting with a professional or a knowledgeable RV dealer can be invaluable. They can offer insights specific to your RV model and recommend the best generator options.

TL;DR: A generator that is easy to install, wire in to the RV system and with sufficient power outlets is an ideal choice.

Balancing Cost and Efficiency

Cost is always a consideration regarding the generator size required for motorhomes, but it's just part of the equation.

What I've found is that efficiency and reliability can't be compromised.

It’s about investing in portable generators that won't just reliably power the RV AC but also meet the overall power needs of other devices without breaking the bank.

The right balance can mean savings in the long run, both in terms of fuel and maintenance.

For example, let's say a basic portable generator costs around $500 but has a lower efficiency and higher fuel consumption.

Over a year, the fuel and maintenance costs might add up to an additional $300.

On the other hand, a more efficient model might cost $800 upfront but only $100 in additional annual costs due to better fuel efficiency and lower maintenance needs.

Over a few years, the initially more expensive model proved to be more cost-effective.

It's about looking beyond the price tag and considering the long-term savings in fuel and maintenance, ensuring that your investment is economical and beneficial in efficiently powering your RV's essentials.

TL;DR: Look for a more energy efficient and a reliable generator that can save you from running and maintenance costs in the long run.

Campground Compatibility

Choosing a generator isn't just about what happens inside the RV. It's also about where you can park it.

Different campgrounds have their own rules regarding generator size and noise levels.[2]

I always consider this when selecting RV generators because it can really open up or limit your RV park options.

A smaller generator can be the ticket to more serene and widely accepted camping experiences in different RV parks than a larger generator.

TL;DR: Different camp grounds have different rules for generator sizes. Most are widely accepting of smaller generator as compared to larger or louder ones.

Determining the Minimum Requirement

Figuring out the minimum generator for RV AC and other crucial appliances is like solving a puzzle.

It's not just about keeping things running; it’s about ensuring they run smoothly and efficiently.

This careful calculation helps avoid any unnecessary bulk or excess power, streamlining the RV experience and focusing on what's essential.

So, how do you determine this?

Simple. Once you have assessed the total wattage needs, add a buffer of about 10-20% to this number for safety and unforeseen power needs.

This total gives you the minimum generator size required to power your RV efficiently without overburdening the generator, ensuring everything operates at its best.

TL;DR: Add up the wattage of all the ACs and appliances you plan to run at a given time and then add a 10-20% margin for determining the least generator wattage rating you need.

Environmental Factors To Consider

When choosing a generator for RV air conditioners, consider environmental aspects like windows and insulation in the RV, as these can affect the efficiency of the air conditioning and, consequently, the power required.

From personal experience, I’ve seen that taking the time to evaluate these aspects thoroughly can make a significant difference in ensuring a comfortable and hassle-free RV experience.

ACLAB Note:

The goal is to find a generator that provides enough power to run your RV AC and other appliances without excess capacity that goes unused.


How to Calculate the Size of the Generator

In sizing a generator for an RV AC, one thing I've learned is the importance of thoroughly understanding the AC unit's power demands.

I’ve created this simple formula to find what size generator to run RV AC.

First, determine the wattage of the AC unit.

TL;DR: For AC units rated in BTUs, convert these to watts (1 watt = 3.41 BTU) for accuracy.

Consider a standard 13,500 BTU RV air conditioner, which typically converts to about 1,350 watts of running power.

However, the starting power or wattage, crucial for the initial power surge, is significantly higher.

This is a detail often missed but critical in selecting the appropriate generator size.

Similarly, while a 2,000-watt generator exceeds the running wattage of the AC, it might falter under the startup power.

In such cases, opting for a generator with around 3,000 watts is a safer bet to handle the load without strain.

Next, I check my usage pattern in my travel trailer: will I run multiple appliances simultaneously?

The right generator should provide enough power for all your appliances, RV's square footage, and amp requirements, factoring in fuel source, whether gas or clean energy, like a solar panel, and any soft start features in your AC.

TL;DR: The generator size can be determined by adding up the starting wattage of all the ACs, the wattage of the appliances, and then adding a 10-20% extra margin. You can also determine through typical RV square footage and amp requirement.

How Are BTUs And Wattage Related?

British Thermal Unit (BTU) and wattage are both measurements used by air conditioners, but don't have equal values.

BTUs measure the heat output of devices like air conditioners, while watts measure the energy they consume.

As mentioned above, you can use these two units to determine the size of generator needed to run an RV AC.

RV AC Size BTU

RV AC Size Per Wattage

Generator Size (Watts)

11,000 BTU

1,100 watts

2,000 watts

13,500 BTU

1,350 watts

3,000 watts

15,000 BTU

1,500 watts

4,000 watts


Generator Size In Relation To AC Wattage

In my experience, figuring out how many watts the generator needs, particularly with two AC units, has been a learning curve.

For instance, if each AC unit requires the same amount of wattage, about 3000 watts to start and 1500 watts to run, a generator of at least 4500 watts is necessary to prevent overload on those hot days when both ACs are needed.

On the other hand, opting for a 7000-watt generator might seem safe, but it often leads to unnecessary fuel consumption and costs.

It's about finding that middle ground where the generator comfortably meets the demands without being overkill.

The right balance ensures that the AC generator requirements are met, as well as the requirements of other appliances you need to run.

This approach ensures smooth operation and cost-effectiveness, balancing power needs with efficiency.


Generator Size in Relation to AC BTU

My experience with different RV setups has taught me the importance of aligning generator size with the AC’s BTU.

A generator that can provide that extra power is vital for maintaining a comfortable temperature, especially in extreme climates.

I remember times when an underpowered generator meant either sweltering heat or chilly nights, struggling to keep the AC units at peak efficiency.

On the other hand, choosing a generator too large for the AC's BTU can be a costly error, leading to inefficient fuel usage and higher operational costs.

The key is in the balance – ensuring the generator can support the AC's demand without overworking or underperforming.

TL;DR: Choose a generator that has a higher supply wattage rating as compared to the required wattage of all the appliances combined but do not go overboard. Generators too large can highly uneconomical.


Generator Size In Relation to the Type of RV You Have

In choosing generators, the RV's square feet and own products and appliances inside greatly influence the decision.

30Amp vs 50 Amp RV

The choice between a 30 amp and a 50 amp RV setup is pivotal.

While a 30 amp system might be sufficient for smaller RVs, a 50 amp setup can handle the same load as a 30 amp system but offers the flexibility to power more demanding appliances. 

It's about understanding the energy needs of your RV.

A larger RV, with more appliances and possibly more living space, naturally needs a beefier system to ensure everything runs smoothly without overloading the circuits.

Class of RV

Different classes of RVs cater to varying lifestyles and needs.

For many RV owners, particularly those with larger Class A or Class C motorhomes, the choice of generator is influenced by factors like the size and power needs.

These larger vehicles often require more robust power solutions, especially when equipped with modern conveniences like RV-safe GPS systems and high-end appliances, demanding a careful balance between power capacity and usage efficiency.

What Other Appliances Do You Have?

The other appliances within the RV, ranging from refrigerators to entertainment systems, all add up to the total electricity demand.

It'll also benefit you to get an appliance that offers an eco-mode, allowing you to consume less energy than expected.

It's about understanding the cumulative power needs of these appliances to ensure the generator can handle everything without faltering, providing a seamless, uninterrupted power supply for all onboard amenities.

TL;DR: The amp rating of the RV or the RV class you have can be a great starting point in determining the size of the generator you need.


FAQ

Do I Need an Inverter Generator for My RV?

Inverter generators, known for their efficiency and quiet operation, are ideal for RVs. They provide stable, clean power, which is safer for sensitive electronic devices commonly found in modern RVs. If this is what you’re looking for, you’ll need an inverter generator for your RV.

Can I Use a Regular Generator for the RV?

Yes, a regular generator can be used for an RV. However, they are often louder and less efficient compared to inverter generators. Ensuring the generator's output matches the RV's power requirements is important.

How Many Hours Can a Generator Run Continuously?

The continuous run time of a generator depends on its model and fuel capacity. Typically, generators can run continuously for anywhere between 8 to 20 hours, but it's essential to check the specific model's guidelines to avoid overrunning.

References: 

  1. https://www.researchgate.net/publication/319199808_Watts_your_usage_A_field_study_of_householders'_literacy_for_residential_electricity_data
  2. https://dnr.wisconsin.gov/topic/parks/rules/generator
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Josh Mitchell

Founder

Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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