The FlowFinder is a powered flow hood that works well in all situations. When the duct pressure is low, it zeros the pressure across the measurement plane very accurately so that system characteristics do not change. All powered flow hoods do this fairly well on return/exhaust flows. The FlowFinder is unusual in that it’s zeroing goes down to 1/100 Pa. Most are only good around zero to about 2/10 Pa making the FlowFinder exceptional where pressures are low or where there is an alternative route for the air to flow. It is also better than the rest at supply flows because it separates the jets experienced in the supply direction from the flow measurement. The flow is then measured by an onboard fan that knows exactly what its inlet pressure is and can determine flow accurately using rpm and pressure after it’s been stabilized.
In difficult situations, the FlowFinder will still maintain its 3% accuracy while any passive flow hood can get 20 to 50% errors. LBL’s study shows this well.
The FlowFinder measures 6 to 326 CFM in full zero balance mode and up to 503 CFM in compensated mode. It is super light and small and can measure kitchen exhaust, HRV flows in tight places. The “Killer” application for the Flow Finder is that it can be used on a sales call with a Blower Door to identify and measure duct leakage to outdoors visually and quantitatively. Just use the Blower Door to pressurize the house to 25 Pa, and if smoke moves at the registers, the Flow Finder will measure it allowing the operator to identify the most cost effective work that can be done on a home.
