This document outlines the amp consumption of RV air conditioners based on their BTU ratings, emphasizing the differences between running amperage and startup surge. It also explains the implications of service limits and the need for effective load management in RVs with different electrical configurations.
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Load and amp diagnosis usually requires these tools.
| Tool | Why You Need It |
|---|---|
| 🔧 Best Multimeter for RV | Measure voltage and amp draw |
| 🔧 Best Clamp Meters | Measure actual amp draw per circuit |
| 🔧 Best RV EMS Systems | Monitor voltage under load |
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Understanding the "load spike" is the first step in avoiding tripped breakers. When your compressor kicks on, it briefly spikes power demand. RV rooftop air conditioners use induction motors that require a massive burst of current to overcome inertia and begin rotating—this is the Locked Rotor Amperage (LRA). Once the motor reached speed, the draw drops to the Rated Load Amperage (RLA).
Startup surge is why many RV owners experience breaker trips even when their "average" amps are low. That brief spike can exceed 24 amps on a 15,000 BTU unit—enough to trip a 20-amp branch breaker if the compressor doesn't start instantly. Soft start kits are designed specifically to "buffer" this LRA spike. See best soft start for RV AC for technical comparisons.
Actual draw varies by manufacturer (Dometic, Coleman-Mach, Furrion, Advent) and environmental conditions. Hotter outdoor temperatures increase refrigerant pressure, forcing the compressor to work harder and draw more amps.
| Unit Size (BTU) | Running Amps (RLA) | Startup Surge (LRA) | Peak Wattage (120V) |
|---|---|---|---|
| 8,000 BTU | 8–10A | 12–15A | 1,200W |
| 11,000 BTU | 10–12A | 15–18A | 1,800W |
| 13,500 BTU | 12–14A | 18–22A | 2,400W |
| 15,000 BTU | 14–16A | 22–26A | 3,000W |
Note that low voltage increases amp draw. If your campground pedestal is delivering only 105V instead of 120V, a 13.5k BTU unit pulling 1,500W will see its amperage jump from 12.5A to 14.3A simply to maintain the same power output. This highlights why monitoring campground voltage is critical for AC health.
On a 30-amp service, you have a total of 3,600 watts (30A × 120V). A single 15k BTU AC consumes nearly half of that. If you run the microwave (1,200W) or the electric water heater (1,400W) at the same time, you are guaranteed to trip the main breaker. Staggering your high-draw appliances is mandatory for 30A RVers.
50-amp service is effectively 12,000 watts available across two 120V legs. This is why 50A rigs can run two or even three AC units simultaneously. However, many 50A rigs use adapters to plug into 30A pedestals; when adapted, you are still limited to 3,600W. See the 30 vs 50 amp guide for full wiring details.
The efficiency of an air conditioner drops as the temperature rises. When it is 105°F outside, the condenser coils struggle to reject heat. This increases head pressure in the compressor system. Higher pressure means the motor must work harder, resulting in "amp creep"—where an AC that pulled 13A at 80°F might pull 15.5A at 100°F.
In extreme heat, it is common for RVers to "stack" issues: high ambient heat (increasing draw) + peak campground demand (lowering pedestal voltage) = guaranteed system failure. Using a surge protector with voltage display helps you identify when voltage sags are combined with high amp draw.
A 2,000W-class portable inverter generator (like the Honda EU2200i) has a continuous rating of ~1,800W. While this is enough to run a 13.5k BTU AC, it cannot handle the 2,500W+ startup surge. Without a soft start kit, you typically need a 3,000W minimum generator for a single AC. If you plan to run other loads while cooling, a 3,500W to 4,500W unit is the industry standard. See our generator sizing math for AC for more details.
A dirty filter doesn't just reduce cooling; it increases power usage. When filters or coils are clogged, the system runs longer to satisfy the thermostat, and restricted airflow can lead to frozen coils. A frozen evaporator coil creates a massive restriction, causing the compressor to run continuously at high load. Clean your filters monthly and inspect the rooftop condenser coils annually to keep amp draw at factory specs. Check our AC maintenance schedule for more.
| Tool / Part | Primary Benefit | Notes |
|---|---|---|
| Soft Start Kit | Reduces LRA surge by 65-75% | Run AC on small generators or 30A |
| EMS System | Auto-shuts off on low voltage | Protects compressor from burnout |
| Clamp Meter (True RMS) | Measure actual real-time amp draw | Essential for advanced DIY troubleshooting |
| Voltage Monitor | Real-time pedestal health check | Plug-in inside RV or part of surge protector |
Generally, no. Two 13.5k BTU units draw ~26A running, which is 86% of your capacity. However, their combined startup surges will almost always trip a 30A breaker. It is only possible with soft starts on both units and zero other loads.
No. The blower fan typically draws 2–4 amps. Cooling becomes power-intensive only when the compressor cycle starts.
Actually, the AC itself doesn't change much, but the power source (generator) loses efficiency. If your generator is struggling to maintain voltage, your AC amps will rise to compensate.
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If you're diagnosing RV electrical or appliance problems, these guides may help:
RV AC Troubleshooting Flowchart | RV Air Conditioner Upgrade | RV Mini Split Air Conditioner | RV Mini Split Installation | Best Mini Split for RV | RV Mini Split Solar Power | Rooftop AC vs Mini Split | RV AC Not Cooling | RV AC Running But Not Cooling Enough | RV AC Airflow Problems | RV AC Hard Start Capacitor Guide | When to Replace RV AC vs Mini Split | RV AC Compressor Failure Symptoms | RV AC Freezing Up | RV AC Short Cycling | RV AC Leaking Water | RV AC Fan Running But No Cold Air | RV AC Compressor Not Starting | RV AC Capacitor Failure | RV AC Capacitor Replacement | How To Test RV AC Capacitor | How To Test RV AC Voltage at Unit | How To Clean RV AC Evaporator Coils
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Last updated: March 2026 · Reviewed for technical accuracy