  The integration of renewable energy sources increases the complexity in
mantaining the power grid. In particular, the highly dynamic nature of
generation and consumption demands for a better utilization of energy
resources, which seen the cost of storage infrastructure, can only be achieved
through demand-response. Accordingly, the availability of energy and potential
overload situations can be reflected using a price signal. The effectiveness of
this mechanism arises from the flexibility of device operation, which is
nevertheless heavily reliant on the exchange of information between the grid
and its consumers. In this paper, we investigate the capability of an
interactive energy management system to timely inform users on energy usage, in
order to promote an optimal use of local resources. In particular, we analyze
data being collected in several households in Italy and Austria to gain
insights into usage behavior and drive the design of more effective systems.
The outcome is the formulation of energy efficiency policies for residential
buildings, as well as the design of an energy management system, consisting of
hardware measurement units and a management software. The Mj\"olnir framework,
which we release for open use, provides a platform where various feedback
concepts can be implemented and assessed. This includes widgets displaying
disaggregated and aggregated consumption information, as well as daily
production and tailored advices. The formulated policies were implemented as an
advisor widget able to autonomously analyze usage and provide tailored energy
feedback.
