Dometic FJX4 2200 vs FJX7 2200: Choosing the Right Portable AC

Aug 12, 2025

Roasting in your caravan? It’s time for the Dometic FJX4 vs FJX7 showdown in Caravan and Motorhome Air Conditioning. Short answer? FJX4 is compact and efficient, FJX7 packs more power and features. But which suits your setup best? Stick around—we’ve crunched the cool facts for you.

The Key Difference: Fixed-Speed vs. Inverter Compressor

When comparing the Dometic FJX4 2200 and FJX7 2200, the main difference is in the compressor type. The FJX4 uses a fixed-speed compressor. The FJX7, on the other hand, features an inverter compressor.

This difference affects energy usage, cooling performance, and operational sound. It's a key factor when deciding which unit fits your travel style.

Dometic rooftop air conditioner showcased on a black background.

How a Fixed-Speed Compressor Works (FJX4)

The fixed-speed compressor in the FJX4 runs at a single constant speed. Once it reaches your set temperature, it switches off. When the temperature rises again, it switches back on.

This on-off cycling can be a bit noisy and less energy-efficient. However, it’s simple, reliable, and gets the job done.

How an Inverter Compressor Works (FJX7)

The inverter compressor in the FJX7 adjusts its speed based on cooling demand. Instead of turning off completely, it slows down when less power is needed.

This results in smoother temperature control and quieter performance. It also reduces energy spikes, especially during start-up.

The Impact on Performance, Noise, and Efficiency

The FJX4 may be more affordable, but its fixed-speed design uses more energy and creates more noise. The FJX7, with its inverter technology, offers improved efficiency and comfort.

If you value quiet nights and lower running costs, the FJX7 has the upper hand.

Dometic FJX4 2200 vs FJX7 2200: A Detailed Comparison

Technical Specifications

Cooling and Heating Capacity

The FJX4 provides 14,000 BTUs of cooling. The FJX7 increases that slightly to 14,500 BTUs.

While the difference is minor, the FJX7 handles slightly larger areas or tougher heat conditions better. That makes it a more powerful option for high-demand settings.

Dimensions and Weight

The FJX4 measures 24" x 13" x 12" and weighs 65 lbs.
The FJX7 is slightly larger at 25" x 14" x 13", with a weight of 70 lbs.

The compact FJX4 is easier to install in tight spaces. The FJX7 offers a sturdier build with minimal size increase.

Power Consumption and Start-up Current

Power use differs slightly. The FJX4 draws around 1,200 watts, while the FJX7 uses 1,350 watts.

Despite the higher power draw, the FJX7’s inverter tech makes it more efficient during continuous operation. This can make a big difference for long-term use.

Features and Technology of Dometic FJX4 2200 vs FJX7 2200:

Quiet Operation and Sleep Mode

The FJX7 runs quieter at 48 dB, while the FJX4 operates around 52 dB. Both include a sleep mode that reduces fan speed and noise overnight.

For light sleepers, this feature is a game-changer. You can stay cool without sacrificing rest.

CleanAir Technology

Both models support air filtration and help maintain a fresh internal climate. The FJX7 goes a step further with upgraded air distribution, which improves circulation.

This helps avoid hot spots and makes the entire space more comfortable.

Smart Connectivity (Dometic Climate App)

Both the FJX4 and FJX7 are compatible with Dometic's mobile app. You can adjust temperature and fan settings via smartphone.

The FJX7 also includes a backlit remote and more advanced timers. These are particularly handy for late-night adjustments.

Air Distribution and Controls

Airflow is smooth and directional in both models. However, the FJX7 uses a refined air distribution system for even cooling.

The controls are also more responsive and intuitive. This makes fine-tuning your climate quicker and easier.

Price and Value

Initial Purchase Cost

The FJX4 is the more affordable option. It offers solid performance without all the bells and whistles.

The FJX7 is pricier due to its inverter compressor and smart features. It’s an investment in comfort and long-term efficiency.

Long-Term Running Costs

Despite its higher upfront cost, the FJX7 tends to use less power over time. That can reduce your energy bills—especially if you travel often or camp in hot climates.

The quiet operation and extra control options may also add value in the long run.

White motorhome with Dometic air conditioner parked on a grassy mountain slope with awning extended and people relaxing outside.

Which Dometic Air Conditioner is Right for You?

Who Should Choose the FJX4 2200?

Ideal for Campers on a Budget

If you're looking for an effective, reliable unit without the premium price, the FJX4 is a great fit. It suits budget-conscious travellers who still want to stay cool.

When Consistent Performance is Enough

The FJX4 delivers dependable cooling in small-to-medium spaces. If you don't need fancy controls or silent operation, it covers all the essentials.

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