The NZERTF includes numerous mechanisms to heat and cool the home, and researchers examined two of these in a side-by-side manner over the course of an entire year. The two systems, a “conventional” heat pump (rated SEER = 16 Btu/Wh, rated HSPF = 9 Btu/Wh) utilizing conventional metal ducting and a “small-duct, high-velocity” system (rated SEER = 14.0 , rated HSPF = 8.35 ) were alternated on a weekly basis to assess (a) ability to deliver required thermal conditions, (b) energy efficiency, (c) moisture removal capability, and (d) noise.
The two systems performed comparably in all aspects over the course of the year. The figure below shows the daily energy consumption of each system during the summer as a function of the daily cooling degree days. Little difference is seen between the two systems. A full report is currently being written to provide detailed results for the year.