A system and method to monitor the condition of a structure is provided. In one embodiment, a sensor node can include a power supply that can scavenge available energy, a sensor for sensing conditions in the immediate environment, and a communications interface for communicating the sensed operating conditions. Readers can be used to acquire data from the sensor nodes. In one embodiment, the readers can determine if the data from the sensor nodes is an exception and, if so, determine whether trend data is sufficient.