Let’s talk first about direct advantages to the end user. Major advantages are:

• Energy savings for the life of the system (Generally many years via lower CFM requirements due to UL or other certification testing.)
• Proven construction methods and materials due to hood certification .
• Use of variable speed fan technology when acceptable to local authority.
• Proven designs for pulling contaminated effluent off the cooking equipment.
• Smaller exhaust fan due to lower CFM needs.
• Smaller CFM needs equal smaller duct size out to roof.
• Smaller duct size translates to a smaller duct shaft in larger buildings.
• The reputation of a company who invested in developing a tested product.

What are the disadvantages?

• A non-listed hood must develop the CFM requirements by square footage, resulting in considerably higher air requirements vs. CFM per linear foot for listed hoods. See reference below.
• Higher CFM requires larger ductwork, duct enclosures and a larger fan.
• More exhaust CFM translates to more make-up air being required, increasing the cost of conditioned air (heating and cooling) requirements.
• Fabrication by a shop that may not follow industry related best practices.
• Substitution of materials or gauges of metal.
• Poor welding practices.
• Structurally weaker due to less bracing or stiffening channels.