ARLINGTON, Va. - The Air Conditioning Contractors of America (ACCA) has introduced ACCA DuctWheel, the association's first software application developed exclusively for the iPad. It is available for purchase in Apple’s iTunes store.

ACCA DuctWheel is a new mobile version of ACCA’s Duct Sizing Slide Rule, which is used by contractors to determine proper sizing of residential duct systems in accordance with Manual D, the national accredited standard for residential duct design. Using the DuctWheel app instead of the standard duct slide rule, contractors and designers can lock the wheel in place, zoom in for easier reading, flip between two wheels for different calculations, or take a screenshot of the wheel in position.

Contractors can use the app to: size metal ducts, lined metal ducts duct board airways, and wire helix flexible ducts; convert round shapes to equivalent rectangles; correlate available pressure with total effective length and friction rate (Manual D sizing calcula­tions); convert velocity into velocity pressure and vice versa; and correct for altitude and temperature. An instruction guide is included with the app purchase.

“DuctWheel features the same, easy-to-use wheel interface that technicians and contractors have been using for years. They already know how to use it to get accurate results,” said Kevin W. Holland, ACCA senior vice president for Business Operations & Membership. “But DuctWheel never wears out, and it’s even easier to use than a standard slide rule - since you can lock it in place, zoom in, even take a screenshot. It’s the only mobile duct measurement app that is powered by Manual D, and it’s the only duct sizing app created exclusively for the iPad - taking full advantage of native iPad graphic and screen capabilities.”

The ACCA DuctWheel app works exclusively on iPads using iOs version 4.2 or higher, and costs $19.99 in the Apple iTunes store.

To learn more about the new app, go to

For more information on ACCA, visit

Publication date:04/25/2011