Exhaust Fan 20" for Riga XL Greenhouses

The Riga 20" Exhaust Fan is the highest-capacity ventilation option in the Riga exhaust fan lineup, engineered specifically for Riga XL greenhouses. Its extra-large 20" blade delivers the high-volume air exchange needed to keep the largest hobby greenhouse structures cool, dry, and productive year-round.

Why Proper Greenhouse Ventilation Matters

Without active airflow, greenhouse temperatures can climb 20–30°F above outdoor levels on sunny days, triggering heat stress, fungal disease, and crop loss. In an XL-footprint structure, passive roof vents alone are rarely sufficient — a powered exhaust fan mounted high on the back wall creates a negative-pressure draw that pulls fresh air through intake vents at the opposite end, the most effective ventilation strategy for large greenhouse volumes.

Key Features

• 20" blade diameter — maximum CFM airflow for Riga XL footprints
• Requires a 20.25" × 20.25" wall opening — fits standard Riga XL panel cutouts
• Pre-wired with a 9-foot grounded power cord — plug-and-play on standard 110–120V household power, no electrician required
• High-wall placement — installs near the ridge or above the rear door for maximum heat and humidity extraction
• Pairs with a thermostat controller — add automatic temperature management for hands-free climate control

Compatible Greenhouse Models

This fan is sized and rated for:

• Riga XL greenhouse models

For smaller Riga models, see our 12" Exhaust Fan (Riga 2–4) and 16" Exhaust Fan (Riga 5) options.

Installation Overview

Cut a 20.25" × 20.25" opening in the polycarbonate panel high on the back wall — typically above the rear door on XL models so the fan can rest on a structural member. Insert the fan, bolt it through the flange holes, and seal the edges with neutral-cure silicone. Pair with passive intake vents or louvers on the front wall near ground level for a full cross-ventilation circuit. Detailed steps are included in the Riga XL assembly manuals; Exaco also provides a dedicated installation video: "Riga XL Fan Kit Installation Instructions."

Frequently Asked Questions

What size opening does the 20" exhaust fan require?
The fan requires a 20.25" × 20.25" square opening in your greenhouse wall panel.

Does this fan need to be hardwired?
No. It comes pre-wired with a 9-foot grounded plug-in cord and runs on standard 110–120V household power — no electrician required for basic installation.

Can I use this fan with a thermostat?
Yes, and it is highly recommended. A thermostat controller automatically turns the fan on and off based on your target temperature. If you also use an intake shutter vent, a simple plug splitter lets both units run from the same thermostat.

Where should I mount the fan?
High on the back (leeward) wall, ideally above the rear door on XL models so it rests on a structural member. Position it opposite or diagonal from an intake vent to create an effective cross-breeze.

Does the 20" fan come with a warranty?
Yes. It carries the manufacturer’s standard warranty (typically 2 years on the motor, 1 year on other parts). It is not covered under the Riga greenhouse’s 10–15 year structural warranty.

What is the difference between the 12", 16", and 20" exhaust fans?
The 12" fan fits Riga 2–4 and Victorian J-Vic/VI models; the 16" fan fits the Riga 5 and Victorian VI 34–46; and the 20" fan is designed exclusively for the Riga XL. Choose based on your greenhouse model for optimal airflow.