A 30–45 ft Class A motorhome gives you a spacious interior and a more comfortable long-distance travel experience. But as the coach gets larger, the awning installed on it is often larger as well.

On many large Class A motorhomes, the main patio awning can reach 16, 18, 20, or even 21 ft. At these sizes, choosing the right RV awning involves more than simply deciding between manual or electric.

The key questions are:

• What size awning will actually fit your Class A motorhome?

• Which structure is better for your coach—vertical-arm or cassette?

• Should you choose a manual or electric RV awning?

• What safety and wind-related features should you consider?

• Should you choose one large awning or two smaller awnings?

• Which brand and replacement approach best fit your long-term needs?

Below, we’ll go through these points in order and show you how to choose the right awning for a large Class A motorhome.

 

1. Start With Vehicle Fitment, Not the Brand

One of the most common questions when shopping for a Class A awning is: “My motorhome is 40 ft long. What size awning should I buy?”

But motorhome length does not determine awning length. A 40 ft Class A does not automatically need a 21 ft RV awning.

What matters is the available mounting space on the passenger side. Before choosing a size, check the entry door, slide-outs, windows, storage doors, lights, vents, body trim, existing brackets, and available space for the awning arms.

For example, one 40 ft Class A may have nearly 20 ft of uninterrupted wall space for one large awning, while another may have multiple slide-outs and be better suited to two shorter awnings.

So before comparing brands, determine what structure and size can actually fit your coach.

 

2. What Awning Size Should You Start With?

 

 

This is only a starting point. Whenever possible, confirm factory-reinforced mounting locations with the RV manufacturer or dealer.

If an 18 ft awning already covers your entry door, patio table, and main outdoor area, there may be no reason to install a 21 ft awning simply because it fits. Larger sizes also mean a longer roller tube, more fabric, more weight, more wind-exposed area, and greater installation demands.

A better rule is: choose the awning that covers the space you actually use—not simply the largest awning that fits.

 

3. Vertical-Arm or RV Cassette Awning?

Large Class A motorhomes generally use one of two main designs.

Vertical-Arm Roll-Out Awning

Vertical-arm roll-out awnings, such as Awnlux W5600/W5700, Dometic power awnings, Carefree Eclipse, and Lippert Solera, use a roller tube with arm assemblies mounted along the RV sidewall.

Their main advantage is serviceability. The motor, arms, fabric, and roller tube are relatively independent, so repairs and replacement parts are usually more straightforward. This design is especially practical when replacing an existing traditional RV awning and reusing the original installation area.

Lateral-Arm / Full-Cassette RV Awning

A lateral-arm or full-cassette RV cassette awning, such as Girard G-2000/NOVA II or Carefree Mirage, has no long vertical arms. The arms extend from the cassette, and the fabric and mechanism are stored inside the housing when retracted.

The advantage is integration: a cleaner sidewall and an unobstructed patio area, which is attractive on luxury Class A motorhomes and diesel pushers. The trade-off is greater system complexity and more dependence on proprietary motors, controllers, sensors, arms, and specialized service.

The choice is therefore less about “low-end vs. high-end” and more about serviceability vs. integration.

 

4. Manual or Electric?

A manual awning such as the Awnlux W5600 appeals to owners who prefer mechanical simplicity. It has fewer electrical failure points and can be easier to maintain, making it attractive for boondocking and remote travel.

The trade-off is convenience. Manually extending and retracting an 18–21 ft awning is not as easy as using a powered system.

An electric motorhome awning is more convenient, especially when weather changes quickly. But when comparing powered products, ask more than whether they have a motor.

If the motor, battery, or electrical system fails, how do you retract the awning?

Some systems require access to or removal of components near the drive mechanism. That can be difficult when the awning is mounted high on a Class A. Awnlux powered awnings retain an Emergency Hand Crank method so the awning can still be retracted if the electrical system fails.

For a large electric motorhome awning, the emergency retraction procedure deserves serious attention.

 

5. Wind and Safe Operation

Wind matters, but one wind-rating number does not describe every real-world condition. Awning width, projection, mounting height, pitch, wind direction, gusts, fabric condition, and RV sidewall structure all affect how an awning behaves.

The most practical questions are:

• Can it retract quickly?

• Does it offer wind or motion detection?

• Is there a manual backup if the automatic system fails?

Wind or motion sensors can be useful backup protection, especially if the owner is inside the RV when conditions change. But they should not be treated as permission to leave an awning open in strong wind.

A simple rule still applies: if the fabric begins to flap or the weather is clearly deteriorating, retract the awning.

 

6. Look Beyond Width—Projection Matters Too

Width is only part of usable shade. A 21 ft × 8 ft awning is wider than an 18 ft × 10 ft awning, but the second projects farther from the coach.

If your main goal is to shade outdoor tables, a BBQ area, the entry door, or the patio during midday sun, projection can be just as important as width.

Compare width × projection, not width alone.

 

7. For a 40–45 ft Class A: One Large Awning or Two?

A single large awning works best when the passenger side has a long, uninterrupted mounting area. It gives you one control and one continuous patio zone.

Dual awnings can make more sense when the coach has multiple passenger-side slide-outs or separate front and rear outdoor areas. They allow independent control, avoid spanning obstacles, and reduce the span of each individual awning.

So a 40–45 ft motorhome does not automatically need one 21 ft awning. The layout should decide.

 

8. How Do the Main Brands Compare?

 

If luxury appearance and integration are the priority, Girard or Carefree cassette systems may be the better fit.

If your coach already uses Dometic or Solera and the main structure is still in good condition, repairing within the existing system can be the simplest choice.

Awnlux W5600/W5700 are aimed at owners who want a complete traditional awning replacement rather than converting to a more complex roof-cassette system. W5600 emphasizes manual simplicity; W5700 adds 12V power operation and emergency manual retraction. Core items such as fabric, motors, and arms can also be serviced as separate replacement parts.

 

9. Repair or Replace?

Do not judge the decision only by the part that failed today.

Repair usually makes sense when the problem is limited—for example, aged fabric, one switch, a gas strut, or an end cap—while the roller tube, arms, and motor remain in good condition.

Compare complete replacement when several problems appear together: worn fabric, an unreliable motor, bent arms, roller-tube sagging, an aging controller, expensive proprietary parts, or rising labor costs.

The useful comparison is total repair cost vs. complete replacement cost.

 

10. Large-Awning Support: Optional, Not Required

On an 18–21 ft awning, the center of the long roller tube deserves more attention because it carries its own weight plus the rolled fabric and experiences vibration during travel.

Roller Cradle — Supports the center of a long roller tube while the awning is retracted.

Center Support — Helps reduce center sagging and maintain fabric shape while the awning is extended.

Anti-Flap Clamp — Helps reduce fabric movement in light wind.

These are optional support accessories, not substitutes for proper installation or retracting the awning in severe weather.

 

11. Check These Items Before Ordering

Before ordering any recreational vehicle awnings for a Class A, confirm:

1. Existing awning size

2. Available wall space

3. Mounting height

4. Entry-door clearance

5. Slide-out clearance

6. Windows, lights, vents, storage doors, and other obstacles

7. Suitable structural reinforcement behind the mounting area

For traditional patio awnings such as Dometic or Awnlux, confirm the arm center-to-center measurement. For a cassette awning, measure the overall assembly and mounting area.

Frequently Asked Questions

What size awning should I choose for a 40 ft Class A?

For many models, 18–21 ft is a reasonable range to evaluate, but the final size depends on available passenger-side mounting space.

 

Is a 21 ft RV awning always better than an 18 ft awning?

No. If an 18 ft awning already covers the patio area you use, the extra span may add little practical value while increasing weight and wind exposure.

 

Is a vertical-arm or cassette awning better?

Choose a cassette system for cleaner luxury integration and an open patio. Choose a vertical-arm roll-out when serviceability and straightforward replacement are higher priorities.

 

Is manual or electric better?

Manual systems offer mechanical simplicity. A 12V electric awning is more convenient for frequent use, but you should also confirm an emergency manual retraction method.

 

Is a wind sensor required?

No. It can be useful backup protection, but it does not replace active weather awareness and timely retraction.

Conclusion: The Right Fit Matters More Than the Biggest Size

For a 30–45 ft Class A motorhome, choose an RV awning based on available installation space, structure, size, operation, and long-term serviceability—not simply the largest size or highest price.

For larger awnings, optional supports such as a roller cradle, center support, or anti-flap clamp can be added when needed.

If you are not sure which awning is right for your Class A, contact Awnlux. Send us your motorhome model, current awning size, and a passenger-side photo, and we can help you confirm the appropriate size and installation solution.