The upcoming quarterly presentation isn’t the only thing making this manager sweat.

Seems counter-intuitive, doesn’t it?

Yet, on the east coast, many variable volume air systems deliver air through variable volume diffusers instead of terminal boxes. It’s not used commonly in Wisconsin and the UP, but perhaps it should.

Out East, why does this system get selected?

Initial Cost Changes

  • Lower pressure duct system; leading to a lower duct pressure construction
  • No terminal box reheat piping, plus all the valves, circuit setters, etc.
  • Simple control system

Energy Savings

  • Lower static requirements lead to reduction in fan horsepower
  • More turndown capability (no VAV box min), so greater diversity capabilities
  • More zones accurately controlled; fewer zones overheated or overcooled


  • Improved mixing regardless of mode – heating or cooling; min or max flow
  • Individual thermostat in every zone
  • Draft free in cooling mode

Traditional VAV Box System

Acutherm Therma-Fuser Diffuser System

How to get a proposal?

Send anyone on the Air Flow team your VAV layout, and we’ll provide a Acutherm Thermafuser offering in three days.

The market flinches at the high cost for a self-regulating ceiling diffuser. But who has looked at the system as a whole?

This may be for you, design build contractor, looking for a way to differentiate yourself from all the other VAV proposals.

Or for you, spec narrative writer willing to extend more options than VAV.

Or for you, building owner, looking to keep your tribe of team members happy.

Until next time,

Tom Gelin
Air Flow Inc.
8355 West Bradley Road
Milwaukee, WI 53223


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