Performance and loss analysis of residential photovoltaic (PV) systems are conducted using the sophisticated verification (SV) method. Performance of the various system configurations is quantitatively analyzed and compared in this paper. The south-oriented systems have approximately 22% more reference yield than the systems that are not oriented south. Difference of the module manufacturers shows more than 10% differences of the performance ratio whereas array configuration shows less difference. Imbalance of the string voltages causes system peak power loss and MPP mismatch. This loss cannot be minimized by the DC/DC converter in most of the systems. (C) 2008 Elsevier B.V. All rights reserved.