This paper considers the functional requirements of building energy performance laboratories with advanced capability to test and develop innovative building envelopes and systems. The aim is to contribute to an ongoing discussion on the future of building energy performance testing, which leads to the complementary development of new test facilities and methods around the world. The development of whole building simulator laboratories with the capability to test the energy and environmental performance of full-scale buildings is considered in light of practices used in fire performance and seismic structural performance testing. The design and use of building energy performance laboratories able to mimic dynamic outdoor and indoor conditions is discussed.