What Size Generator do I Need for my RV?

There is nothing quite like driving across the country, seeing an interesting spot, and then setting up camp. There is a lot of freedom that comes with RVing and overall it can be a great past time. I have been on plenty of these trips before but have yet to purchase an RV. I am hoping here in the next ten years when the kids are older the wife and I can start having our own adventures. When that time comes we will need to be prepared with a power source.

Not all RV parks will have power provided. Or, like in the example above, perhaps we do not stop at a park but decide to rough it by setting up camp in the middle of nowhere. Perhaps it is in the middle of summer and the cabin is sweltering. Having an air conditioner could make things much more comfortable. Or, I want some cold beer from the fridge. When these situations arise there is a need for a power source. Now some RVs do come with built in generators, but not all. If you discover that you do NOT have a built in then it is now time to purchase a generator for your RV adventures.

The question though is which one should you purchase? What size do you need? In this article we will take an in-depth look at the various sizes of generators out there as well as what size you will need for your situation. Along with that we will also take a look at the various features and considerations that have to be made before you purchase your generator.


Before we get into determining the right size generator for your needs we first need to discuss the various considerations that should be taken into account. There are many types of generators on the market today and to be honest it can be a little overwhelming with just how many options there are out there. Hopefully after this section you have a little bit better idea on exactly what you are looking for.

The first major factor is if you want a permanent generator that is built into your RV or if you want a standard portable generator. There are pros and cons to both options here. In the case of a permanent generator you are most likely replacing an existing generator that was built into your RV. In these instances your best bet is go through a dealer to ensure that you are buying the right unit. If not you run the risk of purchasing a generator that is too bulky to fit in the compartment or that is not compatible with your recreational vehicle. These permanent generators also have a built-in transfer switch that allows you to easily switch the power over to the generator at the flip of a switch. This makes it very easy to get power going.

The downside of these permanent generators is that they can be expensive, especially if you go through a dealer. Dealers are notorious for high mark-up. So, if you have your heart set on replacing a permanent generator try to see if you can get the part number, make, model from the dealer and then see if you can purchase it somewhere else either online or through an aftermarket parts company. The other con here is rather obvious. The unit is permanent. In other words you will not be able to use it for other applications like you would with a standard portable generator.

Portable generators are great for those of you who wish to either save money or who wish to go with a dual use scenario. Say for example you want a generator with you when you’re RVing but you also want one on hand in case power goes out in your home. Or, you also go camping and need a power source. A portable generator will accomplish these goals. You will also notice that they can be much cheaper then the permanent generator option. The downside here is that you will have to lug the portable unit around with you when you are RVing. In most cases these units are NOT light and can be rather bulky.

It is not just about permanent and portable generators. There are other considerations as well. Another major one is the overall noise that the generator produces. This can be a big deal as generators decibel volume level can range from fifty all the way to one-hundred. That is like a the sound of rain falling all the way to a lawn mower running nearby. Quite the difference there. You will notice that when looking at generators they have a decibel rating. Pay attention to this. To gauge each generators noise level I like to use this decibel chart. It gives you a clear impression on what to expect before purchasing.

One thing you will notice is that when you are looking at decibel levels there are generators marketed as ‘super quiet.’ These generators are known as ‘Inverter Generators.’ These generators are built differently then your standard units. You see a standard generator has two major sections: The engine and the alternator. The engine creates power by burning fuel. That power is fed to the alternator which converts the power to AC electricity. You now have the ability to plug-in your appliances/electronics. An inverter generator operates in a similar fashion only the engine and the alternator work together and actually share some of the same components. This means that there are fewer components in this machine which makes for an overall quieter noise level.

Inverter generators also produce what’s known as ‘Clean Power.’ A standard generator produces ‘Dirty Power.’ What this means is that the standard generator’s power production can fluctuate and is not a constant stream of electricity. The power provided to your electronics is directly tied to the performance of the generator’s engine. So, if the engine stalls, stutters, or does not perform exactly how it should then you can have variables in your power source which can in turn damage your electronics or appliances. An inverter generator on the other hand produces power FIRST as DC and then converts that DC power over to AC through regularly scheduled intervals. This provides you with a consistent power source, or ‘Clean Power.’

Overall inverter generators are a better product. The only downside there is with them is that they can cost significantly more. So, if you are on a budget and noise level/clean power is not a concern then go ahead and get the standard generator model. However, if you want to spend the extra money to get the premium product then opt for the inverter generator model.

Ok folks, a few more points of consideration before we get onto sizing. The next one is the overall weight and dimensions of the generator. As I had mentioned earlier, if you are going with the permanent option then you need to ensure that it will fit in your RV’s compartment. If not then you are going to have a bad time! However, if you are going the portable generator route then you need to ensure that the unit is not TOO big. After all, you need to be able to transport it back and forth. If it is a larger unit then look to see if it has wheels on it to make transportation easier. Also note that inverter generators are lighter then standard models, so there is another feather in the cap of inverters…

Last point to mention here is the fuel type your generator uses. There are variety of options here such as diesel, gasoline, liquid propane (LP), and even solar. There are pros and cons for each type of fuel source here. The most recommended fuel type is diesel. This is because it burns cleaner then gasoline and can actually produce more for your dollar then propane. Chances are your RV also takes diesel so you’ll be looking for diesel pumps in the first place. However, if you are not comfortable with diesel then propane and gasoline will get the job done. Personally, I am not a fan of the solar units as they are inconsistent. They may be great for short camping trips but I want a generator that is going to be reliable.

Generator Size

Now that we have considerations out of the way we can begin to focus on sizing your generator for your recreational vehicle. When I say size I am not talking dimensions or weight of the unit but the amount of watts that the generator can produce. The more appliances and electronics you want plugged into your generator then the higher the watts you are going to need. Generators can range from a few thousand watts all the way up to twelve or thirteen-thousand watts. You may even be able to find some larger then that in standby models.

The best way to determine exactly what size you need is to add up all the watts of the appliances and electronics that you plan to plug-in. Most appliances will have the wattage that they require. However, if you find that some do not then they are most likely displaying their amps. You can calculate the watts using this amperage number. All you need to do is take the amp number times the volt number. The volt number is the type of connection the appliance uses. For example, a coffee maker plugs into your standard one-hundred and twenty volt outlet. So, let’s say a coffee maker uses five amps. Five amps times one-hundred and twenty volts equals six-hundred watts.

Before you start adding up all of the that you will require we need to understand the difference between surge/starting watts versus running watts. You see in some cases, especially on larger appliances, they will need an extra boost of power to turn on. This is known as starting/surge watts. After the appliance has been turned on the surge watts go down and transition into running watts. The point here is that if you have enough running watts but do NOT have enough starting watts then you will not be able to run your appliances using your generator. Some example appliances that will have surge watts are air conditioners, refrigerators, and freezers. Basically anything that is going to have a compressor.

Alright, so now that you know how to find the wattage required for each of your electronics or appliances add them all up and see exactly how much wattage you need. In every instance it is best that you physically add up everything you want to power yourself. I can give you some estimates here but every situation is different and only you know what you are dealing with. That being said, lets take a look at some average wattage usages.

In nearly every case the air conditioner will require the most wattage out of everything in your RV. These things are power hogs and also come with a high amount of starting watts due to the compressor needing to start up. Just like generators, air conditioners come in a variety of sizes. For example, a five-thousand BTU unit will need between one-thousand to fifteen-hundred watts of power (This includes surge watts). A ten-thousand BTU air conditioner will need between fifteen-hundred to twenty-five hundred watts. Lastly, a fifteen-thousand BTU air conditioner will require between three-thousand to thirty-five-hundred watts.

Besides air conditioners some other estimates that we can provide to you are:

  • Hair Dryers – 600-900 watts
  • Electric Grill – 1,200 – 1,800 watts
  • Electric Heater – 1,200 – 1,800 watts
  • Microwave – 1,000 – 1,300 watts
  • Mini Refrigerator – 700 – 1,200 watts
  • Coffee Maker – 500 – 800 watts

In every instance it is best to overshoot the wattage you think you need by around twenty to twenty-five percent. This gives you assurance that you have enough power and also gives you a little bit extra juice in case something else comes up. Let’s do some basic math here to determine what sized generator we need. We need to power a five-thousand BTU air conditioner at fifteen-hundred watts, a refrigerator/freezer at twelve-hundred watts, a coffee maker at seven-hundred watts, and a microwave at one-thousand watts. So, all in we need forty-four hundred watts. If we add another twenty percent then we need a generator that can produce between five-thousand to six-thousand watts.

If that is too much and we only want to spend our money on a four-thousand watt generator then we can shrink some of our list. Perhaps we can hold off on using the microwave which will cut a thousand watts out of our calculation. Another example we can do, which I am not quite a fan of, is to play around with the surge watts. What I mean here is to find the exact surge watts and running watts on some of your appliances. So, if the air conditioner requires fifteen-hundred surge watts but ONLY one-thousand running watts then you could technically plug-in the air conditioner first, wait about a minute, and then plug-in the other appliances. By doing it this way you use fifteen-hundred watts at time of plug-in but afterwards you are only using one-thousand watts.

Personally, I’m not a fan of the above method as there is a lot of finagling just to get power to all of your appliances. The best option here is to just buy exactly what you need or to buy above that and give yourself that twenty percent buffer. Ultimately though, the choice is up to you.


Ok folks, well I believe we have covered nearly everything there is to cover when it comes to sizing a generator for your motor home. As you can see by reading this article there are a lot of considerations and factors that have to be taken into account before purchasing a generator. In most cases though you will find that with RV generators you are safe if you buy a generator between three-thousand to five-thousand watts. There are always exceptions and you should check your own wattage numbers, but you should be fine with these suggested wattage amounts.

To get you started we have a few portable generators we recommend for RV usage. The first is this four-thousand watt model from Champion. It is an inverter generator so it will run very quiet at only sixty-four decibels. It also comes in at only eighty pounds. That is a light weight generator. Lastly, it has a three year warranty to assure you that if something does go wrong you are covered. Just note that this is an inverter model so it will be more expensive.

The other model we will recommend to you is the Durostar DS400S portable generator. This model produces right around the same amount of power as the previous unit but it is about half the price. The reason for this is that this is NOT an inverter generator. It will be louder, bulkier, and produce ‘dirty energy’ rather then ‘clean energy.’ If you are on a budget then get this model, otherwise I am going to steer you towards the inverter model.

I hope that this article was helpful to you and that you were able to find what you are looking for. Generators can be a complicated business and hopefully we were able to clear some things up. Lastly, please note that this article is intended to give advice and informational value only. We here at ToughAssTools are not liable for any damage when it comes to using generators rather it be personal, injury, or property.

Thanks for reading,

Alec Johnson


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