50 years of experience and knowledge




The Design-Aire SL-REV is our standard SL model with reversed air flow direction. These units are typically used to create negative pressure enclosures, where the exhausted air is required to be filtered.  They are also used as air returns in clean rooms that are ducted back into the buildings' HVAC systems.


  • Easy Installation
    The 11.5” height and light-weight housing of these units make them easier to slide into ceilings. The 3-prong electrical cord allows them to be plugged into standard 115V outlets.
  • HEPA Duration
    The variable speed control helps increase HEPA filter life by allowing the motor speed to be increased as the loading on the filter increases. This keeps the airflow consistent and results in fewer filter changes.
  • Energy Costs
    Each unit only uses a maximum of 2.16 amps.
  • Convenient Connections
    A 115V duplex electrical outlet located in the filter housing allows up to 5 units to be connected to and run from one 15 amp circuit.


  • High Efficiency Particulate Air (HEPA) filter rated 99.99% efficient at 0.3 microns
  • Uniform airflow across filter face
  • Durable, light-weight aluminum housing
  • Disposable/washable foam pre-filters, supplied loose to fit beneath HEPA filter
  • Less then 64dba noise levels
  • Duplex electrical outlet, 15A, 115V
  • 15' power cord, 115V – no hard wiring required
  • Sizes: nominal 2’x2’, 2'x3' and 2’x4’
  • 2 Year Limited Warranty


  • Painted Aluminum or Stainless Steel filter housings
  • Ultra Low Penetration Air (ULPA) filter rated 99.9995% efficient at 0.12 microns
  • HVAC collar connections
  • 2" pleated pre-filter in place of standard 1"
  • Minihelic Gauge, to monitor filter loading
  • Sound Insulation Package
  • Suspension Package
  • Drywall Installation Flange
  • Tamper-Proof Speed Control Cover
  • NEW: 230V export option is now RoHS compliant
  • Available with EC motors