This paper presents a case study of a wireless sensor network (WSN) to support energy management utilizing Web services and middleware technologies. The approach presented proposes the integration of WSNs with Ethernet/Internet/XML/Web Service communications into a ‘knowledge and information services’ platform to support energy management which can be accessed via a Web service to support inhabitant actions to reduce energy demand. It is based on the idea of collecting energy information using various wireless devices operating with different communication standards. This is important as there are various communication standards developed for WSNs including ZigBee, 6LoWPAN, Wi-Fi, WirelessHART and ISA100.11a. The hardware components which are needed for a system using one specific communication standard cannot be used directly within another system, due to differences in firmware, radio components, communication standards, and in some cases profile parameters. This is problematic because the components of different systems cannot be mixed and used in combination in order to take advantage of the most useful aspects of products from multiple vendors. The concept and initial testing of the WSN presented in this paper goes beyond current approaches as it uses various wireless devices operating with different communication standards, which can support Web based services for building managers, owners and inhabitants.