Attack moisture at its source. Choose the easy-to-install adjustable grille bathroom ventilation fan kit that features the AXC in-line duct fan and our attractive adjustable ventilation grilles. Vary airflow to suit your needs. Adjustable grille bathroom ventilation fan kits are available with one or two ventilation points. HVI recommends ventilation rates based on 8 air changes per hour. For most bathrooms this works out to 1 cfm per square foot of area, with a minimum of 50 cfm. A bathroom less than 100 square feet: Calculate 1 cfm per square foot of floor area. A minimum of 50 cfm is the required ventilation rate.. A bathroom larger than 100 square feet: To calculate the proper ventilation rate, add the cfm requirement for each fixture; toilet 50 cfm, shower 50 cfm, bathtub 50 cfm, jetted tub 100 cfm. Note: For proper sizing, the static pressure (SP) needs to be calculated.. Includes: AXC remote mount in-line fan, Mounting brackets, Adjustable grille/collar and Clamps. Features: Bathroom ventilation. Multiple ventilation points. Direct shower ventilation. Helpful Tips. AXC fan mounts easily to attic joists with the exclusive Continental Fan mounting bracket. Always use insulated duct in unheated spaces. When direct venting a shower, or if noise is a significant factor, use insulated flexible duct to reduce condensation and/or noise levels. Add a DFC digital fan control for smart control technology and energy savings.