Power Needs: How Many Watts To Run Rv Air Conditioner?

Camping trips are great fun. You want to stay cool inside your RV. This means running your air conditioner, or AC. But how much power does it need?

You ask, “How many watts to run RV air conditioner?” An RV air conditioner needs quite a bit of power. It needs two types of watts: starting watts and running watts. Starting watts are much higher. They are needed for a brief moment when the AC first turns on. Running watts are lower. These are needed to keep the AC running steadily. The amount of watts depends on the size of the AC. Common sizes are 13500 BTU and 15000 BTU.

You also ask, “What size generator for camper AC?” The size of generator you need depends on your AC’s starting watts. It must be big enough for that quick surge. It also needs enough running watts for the AC and any other things you want to run at the same time.

This post will help you figure out your RV AC power needs. We will look at the watts. We will talk about power sources. We will help you pick the right size generator for RV AC. We will also cover how to run your RV AC on generator power and talk about a helpful item called an RV AC soft start kit. Let’s figure out RV AC power consumption.

How Many Watts To Run Rv Air Conditioner
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Why Power Matters for RVers

Knowing about power is important for anyone with an RV. It helps you plan your trips. It helps you choose the right gear. It helps you save money.

Think about power like gas in your car. You need enough gas to get where you are going. You need enough power to run your RV things. The AC is one of the biggest power users in an RV. Its power needs can be tricky because of those starting watts.

If you do not have enough power, things go wrong. Your power cord might get too hot. Fuses or breakers might trip. Your AC might not turn on at all. If you are using a generator, it might stop working. This is why learning about RV air conditioner power requirements is key.

Grasping AC Wattage: Starting vs Running

RV air conditioners use two main kinds of power ratings. These are starting watts and running watts. It is very important to know the difference.

Deciphering Starting Watts

Starting watts are needed for a very short time. This happens when the AC compressor kicks on. The compressor is the main part that makes the air cold. It needs a lot of power to start moving. Think of pushing a heavy box. It takes a big push to get it going. Running watts are like the power needed to keep the box sliding.

Starting watts can be 2 to 3 times higher than running watts. This high surge of power only lasts for a second or two. But your power source must be able to give that much power at that exact moment. If it cannot, the AC will not start. Or it might trip a breaker.

Interpreting Running Watts

Running watts are the power the AC uses all the time it is cooling. Once the compressor is running, it settles into a steady power use. This is the running wattage. It is much lower than the starting wattage. This is the number you see most often listed on the AC unit’s label.

Running wattage is what you need to keep giving the AC to stay cool. This is what drains your batteries over time or uses fuel in your generator.

Typical Wattage for RV AC Units

The wattage an RV AC uses depends mostly on its size. AC size is often measured in BTUs. BTU stands for British Thermal Unit. It tells you how well the AC can cool a space. Higher BTUs mean more cooling power. They also mean more power use.

The two most common sizes for RV ACs are 13500 BTU and 15000 BTU.

13500 BTU RV AC Wattage

A 13500 BTU RV AC is common in smaller to medium-sized RVs.

  • Running Watts: A typical 13500 BTU unit uses about 1200 to 1700 running watts. The exact number can be different. It depends on the brand and model. Look at the sticker on your AC unit for the real number.
  • Starting Watts: The starting watts for a 13500 BTU RV AC are much higher. They can be around 2500 to 3500 watts. Again, this number can change based on the unit.

Knowing these numbers is key for planning your power. Especially for picking a generator size for RV AC.

15000 BTU RV AC Wattage

A 15000 BTU RV AC is found in larger RVs or those needing more cooling.

  • Running Watts: A typical 15000 BTU unit uses about 1500 to 2000 running watts. Check your AC’s label for the exact number.
  • Starting Watts: The starting watts for a 15000 BTU RV AC are even higher. They can be around 2800 to 4000+ watts. This is a big power surge.

So, to run an RV air conditioner, you need a power source that can handle the starting watts for a second and then supply the running watts steadily.

Power Sources for Your RV AC

You can get power for your RV AC from a few places.

Shore Power

Shore power is the power you get from plugging into an power pole. This is usually at a campground or someone’s house. Shore power is often the easiest way to run your AC. It usually gives you enough power.

RV hookups come in different sizes. The most common are 30 Amp and 50 Amp.

  • 30 Amp Hookup: A 30 amp hookup at 120 volts gives you about 3600 watts (30 amps * 120 volts). This is often enough to run one RV AC unit. But you might not be able to run many other big appliances at the same time. If your 15000 BTU AC needs 4000 starting watts, a 30 amp hookup might struggle.
  • 50 Amp Hookup: A 50 amp hookup at 120 volts actually gives you two lines of 50 amps. So it is like having 100 amps total. This is about 12000 watts (100 amps * 120 volts). A 50 amp hookup can easily run two or even three ACs and many other appliances.

Most campgrounds have 30 amp or 50 amp hookups. Some older parks might only have 20 amp hookups. A 20 amp hookup (2400 watts) is usually not enough to start or run most RV ACs, especially a 15000 BTU unit.

Generators

Generators make electricity. They are great when you are camping where there is no shore power. This is called boondocking or dry camping. Running RV AC on generator power is very common.

Generators are rated by the watts they can make. They have a surge wattage (like starting watts) and a running wattage. You need a generator with a surge wattage high enough for your AC’s starting watts. It also needs enough running wattage for your AC plus anything else.

Choosing the right generator size for RV AC is critical. We will talk more about this soon.

Batteries and Inverters

Some RVs have large battery banks and inverters. An inverter changes battery power (DC) into household power (AC). This lets you use regular plugs when you are not plugged in or running a generator.

Running an RV AC on batteries and an inverter needs a very large battery bank. It also needs a very powerful inverter. ACs use a lot of power constantly. This can drain even large batteries quickly. This setup is less common just for running the AC for long periods. It is more for short use or for smaller things.

Picking the Right Generator Size for RV AC

This is a big question for many RVers. What size generator do you need for camper AC? The answer depends on your specific AC and what else you want to power.

The Rule of Starting Watts

The most important number for generator sizing is your AC’s starting watts. Your generator must be able to make that much power for a brief moment. If the generator’s surge rating is lower than the AC’s starting watts, the AC likely will not start. Or it might trip the generator’s breaker.

Find the starting wattage for your RV AC. Look in the AC’s manual. Look on the sticker on the AC unit. If you cannot find it, use the typical numbers we talked about earlier as a guess. A 13500 BTU AC might need 3000 starting watts. A 15000 BTU AC might need 3500-4000 starting watts.

Total Running Load

You also need to think about other things you want to run at the same time as the AC. Do you need lights? The microwave? The TV? The coffee maker? Add up the running watts of everything you might use at the same time as the AC.

Let’s make a simple list of typical running watts for other RV items:

  • Microwave: 1000 – 1500 watts
  • Coffee Maker: 600 – 1000 watts
  • Hair Dryer: 1000 – 1800 watts
  • Converter (charging batteries): 500 – 1000 watts
  • TV: 50 – 200 watts
  • Lights (LED): 10 – 100 watts
  • Toaster: 800 – 1500 watts

You likely won’t run the microwave and coffee maker at the same time. But you might run the AC, the converter, and the TV together.

Calculating Needed Generator Size

Here is how to figure out the right generator size for RV AC:

  1. Find your AC’s starting watts. (Let’s say 3500 watts for a 15000 BTU unit).
  2. Find your AC’s running watts. (Let’s say 1800 watts for the same unit).
  3. List other items you might run with the AC. (Example: Converter 800 watts, TV 100 watts).
  4. Add up the running watts of the AC and the other items. (1800 + 800 + 100 = 2700 running watts).
  5. Your generator’s surge wattage must be higher than the AC’s starting watts (3500+ watts).
  6. Your generator’s running wattage must be higher than the total running watts of the AC and other items (2700+ watts).

So, in this example, you need a generator that can surge to at least 3500 watts and run at least 2700 watts.

Generator names often show their running wattage. A “3000-watt generator” usually means 3000 running watts. Its surge watts will be higher. A 3500 or 4000-watt generator is often needed to start and run a 15000 BTU AC, plus a few other things. A 2500 or 3000-watt generator might be enough for a 13500 BTU AC and a few other things.

RV Generator Size Chart (General Guide)

This chart gives you a general idea for generator size for RV AC. Always check your specific AC’s wattage.

RV AC Size (BTU) Approx. Running Watts Approx. Starting Watts Minimum Generator Running Watts (Just AC) Recommended Generator Surge Watts (Just AC) Recommended Generator Size (Running Watts) for AC + other items
13500 1200 – 1700 2500 – 3500 1500+ 3000+ 2500 – 3500 watts
15000 1500 – 2000 2800 – 4000+ 1800+ 3500 – 4500+ 3000 – 4500+ watts

Note: “Other items” assumes a moderate load like converter, TV, some lights. If you plan to use a microwave, hair dryer, or coffee maker while the AC is running, you will need a larger generator.

Many people choose a generator with 3000 or 3500 running watts. This gives enough surge power for one AC. It also gives enough running power for the AC and common other items. If you have two ACs, you will likely need a much larger generator, perhaps 5000 watts or more. Or you might need two smaller generators linked together if they are inverter types.

The Helper: RV AC Soft Start Kit

What if your generator is almost big enough but struggles with the starting watts? What if you want to run your AC on a smaller generator? Or even from batteries and an inverter? This is where an RV AC soft start kit helps.

How an RV AC Soft Start Kit Works

An RV AC soft start kit is a small device. It is installed on your AC unit’s compressor. When the AC turns on, the soft start kit manages the power flow to the compressor.

Instead of letting the compressor pull a huge amount of power all at once (the starting watts), the soft start kit feeds it power slowly. It ramps up the power needed over a few seconds.

This smooth power delivery greatly reduces the high surge of starting watts. It can lower the needed starting watts by 60% to 80%.

Benefits of an RV AC Soft Start Kit

Adding an RV AC soft start kit has many good points:

  • Use a Smaller Generator: With a soft start, a 15000 BTU AC that needed 3500-4000 starting watts might now only need 1000-1500 starting watts. This means you might be able to use a 2000-watt or 2500-watt generator to start and run it. This is a huge help for running RV AC on generator power, especially with smaller, quieter inverter generators.
  • Run AC on 30 Amp Service Easier: It makes it less likely to trip the breaker on a 30 amp hookup when other things are already using power.
  • Possibly Run on Batteries/Inverter: With a very large battery bank and inverter, a soft start makes it much more possible to start the AC.
  • Less Stress on AC and Generator: The AC compressor starts more gently. This can be better for the AC’s life. It is also easier on your generator or inverter.
  • Run Two ACs on 30 Amp (with two soft starts): In some cases, with two soft starts installed, you might be able to run two ACs at the same time on a 30 amp hookup. This is often not possible without them.

An RV AC soft start kit can be a good choice if you want more flexibility in how you power your AC. It can often save you the cost and weight of buying a larger generator.

Running Your RV AC on Generator Power

Using a generator to run your AC is common for boondocking. Here are some simple tips.

Pick the Right Spot

Place the generator outside in a safe spot. It must be away from the RV. Point the exhaust away from your RV and anyone else’s. Generators make carbon monoxide. This gas is deadly. Never run a generator inside the RV or in a closed space.

Hooking Up the Generator

You will plug your RV’s power cord into the generator. Some generators have a special RV plug (like a 30 amp plug). Others might need an adapter. Make sure the connections are solid.

Starting the AC

Start the generator first. Let it run for a minute or two. This gives it time to get up to full speed and make steady power. Then, turn on your RV AC. It is best to turn the AC fan on first for a few seconds. Then switch it to cool mode. This helps the compressor start more smoothly.

Managing Other Appliances

Remember the total running watts. Do not try to run too many other high-wattage items at the same time as the AC. If you want to use the microwave, turn the AC off first. Or turn off the microwave before turning the AC back on. Using an RV AC soft start kit helps manage this better.

Turn Off Generator Safely

When you are done with the AC, turn it off first. Let the generator run for a minute or two without the AC running. Then turn off the generator. This helps the generator cool down properly.

Following these steps helps keep your generator and AC running well when running RV AC on generator power.

Figuring Out Your Total RV Power Needs

We talked about AC watts. But what about everything else? To really know what size generator for camper AC (and everything else) you need, you must list all your possible power users. This is part of figuring out your total RV AC power consumption combined with other loads.

Make a List

Walk through your RV. List everything that uses electricity.

  • Air Conditioner (note size: 13500 BTU or 15000 BTU)
  • Microwave
  • Refrigerator (runs on gas or electric? If electric, check watts)
  • Converter (charges batteries – check watts)
  • Water Heater (gas or electric? If electric, check watts)
  • TVs
  • Lights (LED or older bulbs?)
  • Outlets (for coffee maker, toaster, hair dryer, charging phones/laptops)
  • Fans
  • Propane Heater (uses power for fan)
  • Anything else you plug in

Find the Watts for Each Item

Look at the item itself. There is often a sticker with power information (volts, amps, watts). Or check the RV’s manual. If you cannot find watts, you can often find amps. Watts = Amps * Volts (usually 120 volts in an RV).

Write down the wattage for each item. Note if it has high starting watts (like the AC, microwave, sometimes fridge).

Plan Your Usage

You will not run everything at once. Think about what you might use at the same time.

  • Scenario 1: AC + Lights + TV + Converter
  • Scenario 2: Microwave + Converter (AC off)
  • Scenario 3: Coffee Maker + Lights + Converter (AC off)
  • Scenario 4: AC + Converter + maybe Charge a Phone

Calculate the total running watts for the scenarios you expect to happen together. Make sure your generator’s running watts can handle the highest total. Make sure its surge watts can handle the highest single surge (usually the AC, but sometimes a microwave can have a high start-up too) plus the running watts of other items already on.

Example Calculation (revisited with more items):

Let’s say you have a 15000 BTU AC.
* AC: 1800 running watts, 3500 starting watts
* Converter: 800 running watts
* TV: 100 running watts
* Lights: 50 running watts (total LED)
* Microwave: 1500 running watts (let’s assume 2500 starting watts)

Scenario 1 (AC, Lights, TV, Converter):
* Total Running Watts: 1800 (AC) + 800 (Converter) + 100 (TV) + 50 (Lights) = 2750 watts
* Highest Starting Need: This happens when the AC turns on while others are running. Starting watts of AC (3500) + running watts of others (800+100+50 = 950) = 4450 watts needed for a second.

Scenario 2 (Microwave, Converter, Lights):
* Total Running Watts: 1500 (Microwave) + 800 (Converter) + 50 (Lights) = 2350 watts
* Highest Starting Need: Happens when Microwave starts. Starting watts of Microwave (2500) + running watts of others (800+50 = 850) = 3350 watts needed for a second.

Looking at these scenarios, you need a generator with:
* Running watts: At least 2750 watts (Scenario 1)
* Surge watts: At least 4450 watts (Scenario 1 start)

This shows that even for one AC and a few other things, you need a generator that can handle a significant surge. A 4000-watt surge generator might be the minimum, which likely means a generator rated for 3000-3500 running watts or more. If you add a soft start kit to the AC, the AC starting watts drop significantly (maybe to 1000-1500). Then the surge needed in Scenario 1 becomes only (1500 + 950) = 2450 watts. A smaller generator could work!

This exercise helps you see your true RV air conditioner power requirements combined with everything else.

Power Management Tips

Making the most of your power helps you stay cool and avoid issues.

  • Insulate: Keep heat out. Close blinds. Put reflective material in windows. Seal air leaks.
  • Shade: Park in the shade if possible. A cover over the AC unit on the roof can help it work better.
  • Run AC Smartly:
    • Start it early before it gets too hot inside. It uses less power to maintain a cool temp than to cool down a hot RV.
    • Use the fan setting when it is not extremely hot. The fan uses much less power than the compressor.
    • Turn off the AC when you leave for a few hours if it’s safe to do so, but be ready for it to use high power to cool down again.
  • Turn Off Unneeded Items: When the AC is running, turn off lights, fans, or the TV if you are not using them. Definitely turn off the AC if you use the microwave, coffee maker, or hair dryer, unless you have a very large power source.
  • Check Connections: Make sure power cords are in good shape and connections are tight. Loose connections can cause heat and use power poorly.

These simple steps can make a big difference in your RV AC power consumption.

Putting It All Together

Running an RV air conditioner needs power. The amount of watts depends on the AC size, especially the high starting watts.

  • A 13500 BTU AC needs about 1200-1700 running watts and 2500-3500 starting watts.
  • A 15000 BTU AC needs about 1500-2000 running watts and 2800-4000+ starting watts.

You can get power from shore power (30 or 50 amp) or a generator. To run your RV AC on generator, you need a generator big enough for the starting watts of the AC plus the running watts of other things you run. A RV generator size chart helps, but figure out your own total needs.

A 3000 to 4000 watt generator is often needed for one AC. A smaller generator or shore power hookup might be enough, especially with an RV AC soft start kit. This kit lowers the high starting watts.

Knowing your RV air conditioner power requirements helps you pick the right gear. It helps you enjoy your camping trips more comfortably.

Frequently Asked Questions (FAQ)

How much power does an RV AC unit use?

An RV AC uses power measured in watts. It uses starting watts (high, brief surge) and running watts (lower, constant use). A 13500 BTU unit might use 1200-1700 running watts and 2500-3500 starting watts. A 15000 BTU unit might use 1500-2000 running watts and 2800-4000+ starting watts. This is its RV AC power consumption.

Can a 2000 watt generator run an RV air conditioner?

Maybe, but it depends on the AC size and if it has a soft start kit. A 2000-watt generator typically has a surge capacity around 2200-2500 watts. This is usually not enough to start a regular 13500 or 15000 BTU AC without a soft start kit, as they need 2500-4000+ starting watts. If you add an RV AC soft start kit, a 2000-watt generator can often start and run a single RV AC. Check the generator’s surge rating and the AC’s reduced starting watts with the soft start.

How many amps does a 15000 BTU RV air conditioner draw?

Amps and watts are related. At 120 volts, Watts = Amps * 120. So, Amps = Watts / 120.
A 15000 BTU AC uses about 1500-2000 running watts. This is about 12.5 to 16.7 running amps (1500/120 to 2000/120).
Its starting watts are about 2800-4000+. This is about 23.3 to 33.3+ starting amps (2800/120 to 4000/120). This high amp draw is why it can trip 30 amp breakers or overload smaller generators.

Can I run my RV AC on a 30 amp hookup?

Yes, most RVs with one AC unit are designed to run on a 30 amp hookup (which provides about 3600 watts). A single 13500 BTU or 15000 BTU AC will usually start and run on 30 amps. However, you might not be able to run other large appliances (like a microwave or coffee maker) at the same time. If you have two ACs, you usually need a 50 amp hookup or soft start kits to run both.

What is an RV AC soft start kit?

An RV AC soft start kit is a device added to your AC’s compressor. It reduces the large surge of power needed when the AC starts. This lowers the starting watts needed by a lot. This lets you use smaller generators or makes it easier to start the AC on 30 amp power or with an inverter.

How accurate is an RV generator size chart?

An RV generator size chart gives you a general idea of what size generator you might need for camper AC. It is a good starting point. But it is best to check the actual wattage numbers on your specific RV AC unit and calculate your total expected power needs (AC plus other appliances) to pick the perfect size generator for RV AC for your situation.

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