1. Bench Type

• Horizontal flow
  Air flows from the back wall forward across your workspace.
  ✅ Great for agar plates, jar inoculation, and spawn bags because the clean air sweeps across your hands and work without turbulence.
  ⚠️ Not ideal if you’re handling large items that block airflow.

• Vertical flow
  Air flows downward from the ceiling filter.
  ✅ Better if your workspace involves bulky bag work or tall equipment.
  ⚠️ Slightly more air turbulence near the work surface vs. horizontal.

For most mushroom growers, a horizontal flow hood is preferred, but vertical works in tighter spaces.

2. Size

• Small hobby setups: 2–3 feet wide (enough for agar transfers and jar inoculation).
• Medium growers: 4 feet wide (can handle multiple jars or spawn bags comfortably).
• Commercial setups: 6 feet or larger (assembly‑line style work).

Think about your future scale—mushrooms multiply fast, and workflow space tends to shrink just as fast.

3. Filtration

• Look for a HEPA filter with ≥99.97% efficiency at 0.3 microns.
• A pre-filter in front of the fan is important—it protects the expensive HEPA and reduces replacement costs.
• Replace filters only with certified HEPA units (not “HEPA‑like” bargain versions).

4. Airflow Quality

• Standard airflow should be 0.3–0.5 m/s (60–100 feet/minute).
• Consistent, non‑turbulent air = consistent protection.
• A good product will list certified airflow speed—if it doesn’t, be skeptical.

5. Build & Cleanability

• Stainless steel or smooth coated surfaces (easy sanitization, no dust traps).
• Rounded corners beat sharp joins (no hidden spores).
• Easy to disassemble panels for maintenance.

For mushroom growing, most cultivators do best with a horizontal laminar flow clean bench, 3–4 feet wide, equipped with a certified HEPA filter (99.97% at 0.3 microns), stainless finish, and stable airflow around 0.3–0.5 m/s.