How does the AQC Energy Calculator work?
The calculator has a set of equations explicitly created to determine a duct’s overall performance based on heat transfer properties. These equations are detailed in a white paper that is available for download from the calculator. AQC determined each rooftop duct system generates energy losses in three main areas: leakage, conduction losses from both insulation and thermal bridging, and losses from fans moving excess air fully lost to the atmosphere. Using ASHRAE climate data, the energy loss is evaluated in each of these three areas for heating and cooling, leading to a total annual energy loss from the (assuming a 24-hour a day, 365-day a year operation) outdoor duct system.
The total energy loss for Q Duct’s near-zero leakage system is compared to the total energy loss of a comparison duct system to find overall energy savings with the Q Duct system. The calculations use AQC’s Q Duct specifications and a comparison’s duct specifications, illustrating that air leakage is the primary energy impact. AQC’s Q Duct exceeds a SMACNA leakage class of 1, while almost all other duct systems have a three or higher leakage class.
The calculator also outputs the peak energy loss in kilowatts for both heating and cooling to aid the utility companies in quantifying a possible rebate.
Inputs and Outputs
Go to the AQC energy calculator and input a few specifics related to your project. Specific inputs include state, city, natural gas & electric rates (each pre-loaded with the national average), duct area, and pressure class along with the R-value and SMACNA leakage class for Q Duct and the comparison duct. Even though Q Duct is standard with SMACNA 1, most of our tested projects have shown zero leakage; hence, a 0.5 leakage class is listed. Also, an R-1 is offered as an option for the calculator even though it is not available to illustrate the impact of leakage over duct insulation value.
The calculator offers an Advanced option that allows the user to change the 4 points from ASHRAE’s weather data that includes the heating and cooling degree days, along with the Heating and Cooling design temperatures. Also, the advanced area allows the user to edit the cooling efficiency, heating efficiency, heating type, fan efficiency, and area of the comparison’s duct 4-bolt flange.
Outputs graphically illustrate the energy savings of Q Duct and the comparison duct. The user can take their cursor to hover over a bar in the bar graph to see the cost of each component of the energy losses. The calculator will also output the peak energy savings in both heating and cooling to assist local utilities with rebate calculations.