Can I leave my RV roof vent fan open when it rains?

Answered by RV Parts Giant · Upland, CA · October 17, 2026

Short answer: Only if something covers it. A MaxxFan Deluxe has a built-in rain shield, so MaxxAir rates it to run in any weather, even while driving. An open-lid fan without a shield needs a FanMate cover clipped over it, and a plain non-powered vent needs a MaxxAir I+ or Maxx II cover. Otherwise close the lid or rely on a rain sensor.

It depends on what sits over the opening, not on the fan motor. Work out which of these four setups you have.

1. A fan with a built-in rain shield: yes

The MaxxFan Deluxe models (for example 00-05100K, 00-07000K) have a permanent rain cover built over the fan. MaxxAir describes the Deluxe as usable in any weather, including while it is raining or while you drive, because the lid never has to open to the sky. The small MaxxFan Mini Plus and Dome bathroom fans also carry a built-in shield or fan guard.

2. An open-lid powered fan: add a FanMate

A powered fan whose lid lifts open (a MaxxFan Plus, the MaxxFan Pivot, or another brand's fan) lets rain in when open. The FanMate cover (00-955001 white, 00-955002 black, 00-955003 smoke) mounts over it:

It clips onto the molded waterproof tabs on MaxxFan and MaxxFan Plus models with no tools, and the Pivot has the same tabs.
Hardware with clips is included for mounting over other fan brands.
MaxxAir recommends it for high-power fans because it restricts airflow very little.
An optional bug screen (00-955202 for white/black, 00-955203 for smoke) fits underneath.

3. A plain non-powered vent: add an I+ or Maxx II cover

For a standard 14" x 14" vent with no fan, the MaxxAir I+ cover (00-933051 translucent white, 00-933052 black) mounts over it so the vent can stay open in any weather; it replaces the original MaxxAir covers 00-933066 and 00-933069. The Maxx II (00-933081/082/083) does the same job with an EZClip hinge.

More on fitting each cover, the gap underneath and the UniMaxx lid: which MaxxAir vent cover fits.

4. No cover and no shield: close it, or let a sensor close it

Among the MaxxFans we stock, only the MaxxFan Plus with electric lift and remote (00-04500K) lists a rain sensor that closes the lid automatically. Every other open-lid model needs someone to shut it.

Quick rule

If you leave the RV with vents open, either the fan has its own shield (Deluxe) or the vent has a cover over it (FanMate, I+, Maxx II). A rain sensor is a backup; a cover keeps working when the battery or the 12V fuse does not.