RV AC Unit Amp Draw: A Complete Guide To Understanding Air Conditioner Power Consumption In RVs

Knowing how many amps your RV air conditioner draws is crucial for safe and efficient travel. The amp draw affects everything from choosing a compatible generator or inverter to preventing dangerous electrical overloads. This in-depth guide explores average amp draw figures, factors influencing power usage, and best practices for RV AC efficiency, all tailored for American RV enthusiasts.

Summary Table: Typical RV AC Unit Amp Draw

AC Unit Size (BTU)	Voltage (V)	Running Amps	Startup Amps	Generator Min. Size (Watt)
9,000	120V	7-8A	16-20A	2000W
13,500	120V	12-14A	25-28A	3000W
15,000	120V	13-16A	28-32A	3500W

What Does RV AC Unit Amp Draw Mean?

Understanding amp draw refers to the amount of electrical current an air conditioner uses while operating. In the RV world, knowing your AC’s amp draw ensures your generator, inverter, and electrical system can handle the load, especially when running multiple appliances. Every air conditioner has two types of amp draws—startup (surge) amps and running (continuous) amps.

Startup Vs Running Amps

• Startup Amps: The initial surge when the compressor and fan kick on is higher than running amps and typically lasts a few seconds.
• Running Amps: The steady current required to maintain operation after startup, usually much lower.

How Many Amps Does A Typical RV AC Use?

The average RV air conditioner (usually 13,500 to 15,000 BTU) draws between 12 and 16 running amps at 120 volts. The startup surge can momentarily spike to 25-32 amps depending on model and power supply.

Common AC Unit Sizes & Their Amp Draw

• 9,000 BTU units: 7-8 running amps, up to 20 amps for startup.
• 13,500 BTU units: 12-14 running amps, up to 28 amps for startup.
• 15,000 BTU units: 13-16 running amps, up to 32 amps for startup.

Smaller rooftop or portable ACs in teardrop campers may use less than 10 amps, while ducted multiple-unit setups require much more capacity.

Why Is RV AC Amp Draw Important?

Managing amp draw prevents overloaded circuits, tripped breakers, or damage to your RV’s electrical system. It also helps you select the correct shore power plug, generator, inverter, or extension cord. Overloading risks fire hazards, damaged electronics, and expensive repairs.

Essential Scenarios Where Amp Draw Counts

• Running Multiple Appliances: Air conditioning, microwave, refrigerator, and more add up quickly. Exceeding an RV’s 30-amp (or 50-amp) limit trips breakers.
• Boondocking (Dry Camping): Generator or inverter sizing must accommodate AC startup surges to reliably cool your interior.
• Hooking Up To Shore Power: Incorrect plug or circuit capacity causes inconvenience and potential damage.

Factors Affecting RV AC Unit Amp Draw

RV air conditioner efficiency and power use depend on numerous factors, so your real-world results may vary.

Key Influencing Factors

• Ambient Temperature & Humidity: Hotter, more humid days require the compressor and fan to work harder, increasing amp draw.
• Age And Maintenance: Dirty filters or worn components decrease efficiency, resulting in higher amp draw.
• Thermostat Settings: Setting the thermostat lower than necessary prolongs compressor operation and increases total amps used.
• Voltage Drops: Extension cords and long-distance wiring reduce voltage, causing the unit to draw extra amps for the same cooling.
• Type & Size Of AC Unit: Larger, ducted systems use more amps than smaller, direct-discharge single-zone models.
• Soft Start Devices: Adding a soft start kit can lower startup amps, making it easier on generators and inverters.

How To Calculate RV AC Amp Draw

Use the formula Amps = Watts ÷ Volts. Most RV rooftop air conditioners are rated for 120 volts AC (VAC). Check your owner’s manual or the data plate.

Example Calculation

• A 13,500 BTU unit rated at 1,550 watts at 120 volts:
  • 1,550 ÷ 120 = ~12.9 amps (running)

The startup surge may be 2-3 times this amount, but only lasts a few seconds.

Choosing A Generator Or Inverter For Your RV AC

Matching the right generator or inverter ensures stable AC operation. Undersized generators can’t handle the surge and may stall or trip.

Minimum Generator Sizing Recommendations

• 9,000 BTU Unit: 2,000W generator minimum
• 13,500 BTU Unit: 3,000W generator minimum
• 15,000 BTU Unit: 3,500W generator minimum

Consider adding a soft start module to allow running larger AC units on a smaller generator or inverter.

Can You Run RV AC On 30-Amp Or 50-Amp Plug?

Most single AC units work fine on a 30-amp circuit. If you have two or more rooftop ACs, you’ll need a 50-amp hookup to run them at the same time, plus other appliances.

• 30-Amp Service: Provides a maximum of 3,600W at 120V (30A × 120V = 3,600W)
• 50-Amp Service: Provides up to 12,000W at 240V (50A × 120V × 2 legs = 12,000W), suitable for large luxury rigs with multiple ACs.

Always check your RV owner’s manual and the amperage rating on shore power to prevent accidental overloads.

What About Running RV AC On Battery Power?

Standard roof-mounted RV air conditioners draw far more current than most battery banks or inverters can provide for long periods. A 13,500 BTU AC using 13 running amps draws about 1,560 watts, or 130 amps from a 12V battery per hour—far exceeding practical battery reserves.

Viable DC Options And Limitations

• 12V Or 24V DC Air Conditioners: Special low-power air conditioners are available for small campers or van conversions, but cooling ability is limited.
• Large Lithium Battery Banks: Some luxury systems with 1,000+ amp-hour lithium setups can run a single AC for 4-6 hours.
• Inverters: Require high surge capacity and may drain batteries rapidly, making boondocking with conventional ACs difficult.

For most RVs, running the air conditioner off battery is impractical without shore power or a generator.

How To Reduce RV AC Amp Draw & Improve Efficiency

Improving air conditioner efficiency not only reduces amp draw but also enhances cooling performance and extends equipment life.

Practical Tips To Lower AC Amp Draw

• Clean filters and vents regularly to improve airflow.
• Park in shade when possible to minimize interior heat.
• Use reflective window coverings or sunshades.
• Close blinds and curtains during the hottest part of the day.
• Install soft start devices to reduce startup amp spikes.
• Seal leaks and insulate walls, doors, and roof.
• Use fans or ventilation systems to circulate air before running the AC.
• Set thermostat at the highest comfortable temperature instead of a very low setting.

These strategies can substantially reduce amp draw, helping your electrical system and generator run more efficiently.

Key Considerations For Multiple Air Conditioners

Larger motorhomes and fifth wheels may have two or even three rooftop units. Each unit adds to the total amp load, so you must ensure your RV is wired for 50-amp service and connected to a 50-amp pedestal or sufficiently large generator.

Sequencer Boards And Load Management

• Sequencer/Delay Boards: Installed to stagger startups, preventing all compressors from starting at once and overloading circuits.
• Load Shedding Systems: Automatically disconnects certain appliances or AC units if amps exceed safe parameters, protecting wiring and breakers.

If you plan to retrofit an extra air conditioner, consult an RV electrician to avoid unsafe overloads.

Common Questions About RV AC Unit Amp Draw

Q: Can I Run My Microwave And AC At The Same Time On 30-Amp Service?

Generally, no. Most microwaves draw 10-13 amps, and a single 13,500 BTU AC draws 12-14 amps. Running both pushes you close to or over the 30-amp limit, especially with other devices active. Use appliances sequentially for best results.

Q: Why Does My AC Trip The Breaker?

This usually means the amp draw is exceeding the breaker or circuit rating. Check for dirty filters, faulty capacitors, weak shore power voltage, or excess load from other appliances. Seek professional help if persistent.

Q: Will A Soft Start Let Me Run My RV AC On A Smaller Generator?

Yes. Soft start modules (like EasyStart or SoftStartRV) reduce the instant startup surge—sometimes by up to 60%—making it possible to run your air conditioner on a 2,000W generator or a lower-capacity inverter than would otherwise be possible.

Q: Are There 12V Air Conditioners For RVs?

Yes, but they’re less powerful than standard rooftop units. These are found mostly in small campers, van conversions, or as spot coolers in sleeping quarters. They’re practical if battery capacity is sufficient, though overall cooling is limited.

Tips For Measuring Your RV AC’s Actual Amp Draw

To get an exact amp draw for your system, use a clamp meter or power monitor (like Kill A Watt). This measures current flow either at the circuit or outlet while your AC is running.

• Measure while the AC is operating under normal load, not just at startup.
• Check both the running and startup (if possible) currents for accuracy.
• Compare against your owner’s manual ratings to ensure performance is normal.

If measured amp draw is significantly higher than manufacturer specs, inspect for dirty coils, low refrigerant, or electrical issues.

RV AC Unit Power Consumption & Costs

Operating an RV air conditioner typically uses 1.3–2.0 kWh per hour for a single unit, depending on BTU rating and weather.

• Example Cost Estimate (30A Service): Running a 13.5k BTU unit for 8 hours at 1.56 kWh/hour would use ≈12.5 kWh. At the U.S. average electricity rate of $0.15/kWh, this is about $1.88 for 8 hours.
• Generator Fuel Usage: Small portable generators may consume 0.3–0.6 gallons of gasoline per hour running a single AC, depending on load and efficiency.

If you’re paying metered campsite electric or calculating generator refueling needs, knowing your amp draw directly affects your travel budget and backup preparations.

RV AC Unit Amp Draw And Safety Precautions

Always check your wiring, breakers, and connections for proper ratings before running your air conditioner. Match extension cord gauges to expected amps; avoid thin or frayed wires. Overloaded or hot wires are a leading cause of RV electrical fires.

• Never use an adapter to plug a 30-amp cord into a 20-amp household outlet.
• Always reset tripped breakers and allow time for units to cool off before trying again.
• If unsure, consult an RV electrician before upgrading air conditioners or modifying circuits.

Summary: Managing RV AC Amp Draw For Reliable Cooling

Grasping your RV AC’s amp draw—and how to manage it—is vital for both safety and comfort on the road. Check ratings, size your generator and inverter wisely, and follow best practices for energy efficiency to enjoy cool, trouble-free travels in any climate.