Transpired solar collector (TSC) ducts were installed at a swine nursery and a turkey brooder farm in eastern North Carolina (NC), USA. Each farm had a Test (TSC duct-equipped) and an identical, adjacent Control treatment. Five swine herds and six turkey brooder flocks were monitored over two heating seasons (2010-2012). Propane uses were reduced by 55 and 27 L/m(2)-yr, respectively, in the swine and turkey barns; reductions were highly variable among herds or flocks and the modest reductions were due to warm weather and use of attic ventilation. Over a 14-d period, both the swine and turkey TSC units increased ambient temperature in the barns by 6 degrees C with a maximum increase of 22.5 degrees C in the turkey TSC. In the swine and turkey houses, calculated energy additions by the TSC were 433 and 81 MJ/yr-m(2) of collector surface area, or 16 and 3 L/m(2), respectively, of propane saved. Calculated propane savings were much lower than measured values. Short-term efficiencies were higher in the swine TSC (>61%) vs. the turkey TSC (39-50%) probably due to the lower face velocity of the turkey TSC which increased collector heat losses. While barn CO2, RH, and temperature values were unaffected by the TSC, it was unclear why animal performance in the Test treatment was better. Simple payback periods for the TSC ducts at both farms were favorable (<5 yr) with government incentives. The TSC ducts were both technically and economically feasible, with incentives.(C) 2013 Elsevier Ltd. All rights reserved.