HVAC performance monitoring system

A system for monitoring the performance of an environmental control system arranged to control at least one environmental characteristic in an environment, the system comprising:

• a monitoring device comprising:
• a sensor data recorder that periodically records sensor data relating to an environmental characteristic from at least one environmental sensor in a sensor log;
• a processor for:
• identifying an activation period during which the environmental control system is expected to be activated to control an environmental characteristic, and generating, in response to identifying the activation period, a data set of sensor data measured during the activation period relating to the environmental characteristic based on the sensor log;
• and
• in response to identifying a start of the activation period:
• adding previously recorded sensor data for a predetermined duration prior to the start of the activation period from the log to the data set for analysis;
• adding further sensor data received during the activation period to the data set;
• after detection of an end of the activation period, continuing to store sensor data received from the environmental sensor to the data set;
• and
• terminating recording of sensor data to the data set a predetermined duration after the end of the activation period;
• a memory for recording the sensor loci and the data set of sensor data measured during the activation period relating to the environmental characteristic;
• and
• an interface for transmitting the data set to an analysis server for analysis;
• the analysis server comprising:
• a server interface for receiving from the monitoring device the data set of sensor data relating to the environmental characteristic measured during an activation period of the environmental control system;
• and
• a processor for analysing the data set in dependence on the target value to determine whether the sensor data within the data set is consistent with an expected response of the environmental characteristic during the activation period;
• and for detecting an underperformance condition in response to determining that the sensor data within the data set is not consistent with the expected response.