Calculating Watts Consumed
Though it’s not hard to find many table and lists on any old RV website about how much electricity each appliance of device consumes, there’s no tool to calculate it.
So guess what? I made a Google Sheets that does exactly that!
- The big red button below will take you there (you don’t even need a Google account).
- Then you can make a copy and calculate exactly your RV generator size.
- It’s as easy as selecting ‘Yes’ or ‘No’ to a list of appliances and devices.
- The spreadsheet will return a minimum wattage total and a recommended total wattage.
If you add your own watt-consumption by device (easy—the spreadsheet already shows industry averages) the recommendation becomes personalized and even more accurate!
Read on to get a full explanation of why you need the power you do and the best generator size for your situation.
The Short Answer: RV Generator Size
Your AC is really the big determining factor. If you have one, you’ll need a lot of power.
If you have a fifth wheel RV or a larger Class A or C, you’re going to need a ton of power. You probably even have a built-in generator.
This article focuses on small campers, teardrops, trailers…the kind of RVs with a portable generator setup.
That means this article covers 30 Amp generator sizes. For bigger RVs you’ll want 50 Amp. Read this article—our complete guide to RV generators—to learn more.
With AC
We get into it later, but if you’ve got a 13,500+, you’re going to need a generator over 3,000W. We recommend this one.
If you have a single 15,000 BTU AC unit, then your best option is getting two small 2,000W generators.
You can hook them up in parallel (connecting them so their combined watts is 4,000W).
Read our review of the best generator to hook up in parallel (Spoiler: it’s a Honda).
Without AC
Awesome! You’re really leaving the comforts of civilization behind.
You’ve also left the boundaries of ‘two parallel generators fits (almost) all.’ So keep reading (and try using the calculator)!
A generator anywhere from 1,600W to 3,000W should keep you going well, but there’s a large price difference within that range.
If you want a fast answer, this is a review of the end-all be-all of a generator that’ll work great for any RV without AC. (It’s a Westinghouse.)
How Much Power Do You Really Need?
There are three categories of power consumption to consider when powering your RV: air conditioning, kitchen appliances and everything else.
The important thing to remember, when choosing a portable generator or other power source, is that not all your devices will be running at the same time.
But What If…
No, not all your appliances will run at the same time.
Maybe your AC will be running most of the time in the summer, but your electric stove will only be running when you cook.
And when you’re cooking, I doubt you are vacuuming or drying your hair all at the same time too.
So you can see that this isn’t a simple sum of watts—though that’s where you want to start.
Running Two Generators in Parallel
This is an awesome solution for the flexible RVer.
Connecting generators in parallel has many advantages
Pros
- Use one when you only need 2,000W or connect them when you need 4,000W
- Two Quiet > 1 Loud
- Portable (you only have to lift one at a time)
Cons
- You Need a Connection Kit (They’re cheap, so this isn’t really a con…)
There are many great generators out there that can run in parallel and are quiet, portable, and small while offered for a good price.
My favorite generator (and a RV SUPPLY Co favorite) is a Honda, the EU2200i.
How Much Power To Run My RV AC Unit?
To run your AC you generator must at least match the starting wattage.
The starting wattage is what an AC takes to ‘wake itself up’. Once it’s awake and running it operates on the running wattage.
| Air Conditioner Unit | Starting Wattage | Running Wattage |
| 13,500 BTU | 2,900W | 1,300W |
| 15,000 BTU | 3,400W | 1,500W |
As you can see, there is a big difference between starting wattage and running wattage—the more the bigger the AC.
DISCLAIMER: These values are averages and estimates over a wide range of different models and specifications. Do not take this as final. RV SUPPLY Co assumes no responsibility whatsoever of any electrical problems.
So How Big Should My Generator Be to Power My AC Unit?
The gap between running and starting watts leaves a lot of room, if say, you have a 3,400W generator for a 13,500 BTU AC.
The generator will work to power it up, but once the AC is on there is about 2,000W to power other devices.
For 13,500 BTU, a 3,400W inverter generator is normally the best option. Read our review of the Champion 3,400W.
What Size RV Generator for 15,000 BTU AC?
15,000 BTU is tricky. Some 3,400 Watts can manage it, some can’t.
The Champion 3,800W is a good option if you don’t plan to have a lot of other devices running simultaneous.
The problem is, at 3,800 Watts, it is not an inverter generator, which means it large and loud.
That’s why hooking two generators up in parallel is such a great option! Read more!
How Much Power Do I Need To Run My RV Appliances?
This section focuses on kitchen appliances.
There are a few items in here that can really start to add up. The good thing is, besides the fridge, these appliances will only get used when you cook.
| Appliance | Starting Wattage | Running Wattage |
| RV Fridge | 500-900 | 180-600 |
| Electric Grill | 1,700 | 1,700 |
| Dishwasher | 1,400 | 700 |
| Microwave | 500-1,000 | 500-1,000 |
| Coffee Maker | 600 | 600 |
| Toaster | 850 | 850 |
DISCLAIMER: These values are averages & estimates over a wide range of different models and specifications. Do not take this as final. RV SUPPLY Co assumes no responsibility whatsoever of any electrical problems.
Does This Mean I Need 10,000 Watts?
No. Of course not. Even if those numbers look high compared to a 2,000 or 3,000 Watt generator, don’t worry.
Besides the electric grill, those items aren’t really too big. You’ll only be using the microwave for much less than 1% of your time in an RV.
Any generator above 2,000W (all recommended on this page) can take it.
If you have an electric stove and a few other bigger appliances (or an AC unit), you should probably consider replacing it with a gas stove, first of all, or getting a generator like the Champion 3,400W.
Other Power Drains In Your RV
It’s not unlikely to have your laptop charging next to your phone next to your airpods.
That said, your personal electronics are tiny compared to air conditioners or appliances.
Those you’ll want a 400-500 Watts ‘spare’. A TV can is 200 Watts; a laptop charging is 100W. A phone is much less.
This table contains the few items of note…
| Item | Starting Wattage | Running Wattage |
| Hair Dryer | 1,500 | 1,300 |
| Iron (the crease-removing kind) | 1,250 | 1,250 |
| Space Heater | 1,250 | 1,250 |
| Vacuum | 1,000 | 400 |
DISCLAIMER: These values are averages & estimates over a wide range of different models and specifications. Do not take this as final. RV SUPPLY Co assumes no responsibility whatsoever of any electrical problems.
Some electrical devices have the same starting and running wattages and some don’t because they have some internal mechanism that needs to start. Once it’s running, it takes less energy to keep it going.
How Much Is Electricity Worth
I thought it would be interesting to add a section of the cost of electricity.
This table shows the rate of electricity in cents per kWh. That’s cents as in $0.10.
kWh is kilowatts (1000 Watts) times hours. One kilowatt hour (kWh) is equivalent to 1000 Watts of power consumed for one hour.
Full credit due to Choose Energy. This is an incredible interactive graphic.
The End, but…
Thanks for reading! We hope you find this helpful. If you have suggestions, content ideas, feedback or want to contribute send us a quick email at info@rvsupplyco.com.
If you want more info, try reading the FAQ section.
FAQ
The full post (and the free calculator) will best answer that question. Briefly…
With no AC, any (quality) generator under 2,500W ought to be fine.
If you only have one AC (less than or equal to 15,000 BTU), I recommend getting two 2,000W generators and hooking them up in parallel.
You will have a decent amount of extra power to run your other devices. Two Honda EU2200is (Review) are your best bet, in my opinion.
With more than one AC, your RV probably runs on 50 Amp service (and might have a generator built in).
Check out this part of our guide to the best RV generators.
A 30 Amp RV, using the power equation, uses 3,600 Watts max (30 Amps X 120 Volt service).
A 50 Amp RV runs two 120 Volt cables at 50 Amps each, the total wattage equal to 12,000 Watts.
This is the amount of service you will receive if you plug into an outlet, the kind you’d find at a campground.
Read this full article to see if you need a generator that matches the total possible power, or if you don’t need that much. Find the best choice!
This is an extremely broad question. The full post (and the free calculator) will best answer that question. However, in short…
With no AC, anything under 2,500W should be fine.
If you only have one (13,500 or 15,000 BTU), I recommend getting two 2,000W generators and hooking them up in parallel.
You will have a decent amount of extra power to run your other devices.
A pair of generators such as the Honda EU2200i will serve you well.
With more than one AC, your RV probably runs on 50 Amp service (and might have a generator built in).
I recommend checking out this section of our guide to RV generators.
A 30 Amp RV can take a maximum of 3,600 Watts (= 30 Amp X 120 Volts).
That said, an RV connected to a generator that produces less will also work, for the total power listed on the generator.
(Most generators under 3,600 Watts are inverters producing 30 Amp current.)
Great question! First off, it depends on the size and number of AC units.
If you only have one (13,500 or 15,000 BTU), I recommend getting two 2,000W generators and hooking them up in parallel. That’ll leave you with a good amount of extra power for your other devices.
A pair of generators such as the Honda EU2200i will serve you well.
Video Explanation
This guy jumps around a lot but he covers what you need to know.