The sensor clamp technology we use is typically within 5% of the true metered readings, however it can vary and be 10% out in some circumstances.
Our products are designed to provide useful indication information showing both live and historic data and usage / generation patterns. It is not meant to be or to replace metering products. Due to the limitations of the current clamp sensors, all products of this type will have a level of inaccuracy. These sensors only measure the current flowing, they cannot measure the voltage or the power factor and assumptions therefore have to be made (Our defaults are 230v and PF 1.0) in the calculations. Equipment capable of such measurements would be relatively costly and have to be wired into the circuit by an electrician.
If you are seeing larger variances, it is normally down to one or more of the following factors:
1) The Sensor clamp is not correctly closed - the clamp should be a loose fit on the cable being monitored, if it is tight the clamp may not be closed properly.
2) Voltage - The default voltage setting on the OWL portfolio is 230V, it should be changed to suit the voltage at the specific installation.
3) Power Factor - The technology used does not take into account power factor of appliances in the home/office. This is very important in climates where air conditioning is deployed as this will often be the main source of consumption within the building. Air conditioning normally has a power factor of around 0.8 – 0.9.
It is possible to fine tune the OWL Intuition configuration to minimise differences between the OWL Intuition readings and the meter readings. Through the web dashboard System menu, click on "Property Voltage" here you can change the default Voltage and Power Factor setting. It is suggested for ease of calculation that you adjust the Power Factor setting. So for example if your system over the course of a day is under reading by say 10%, adjust the Power Factor to 1.1 and click Save. Please remember that the true voltage and true power factor are actually variable, so your improvements will also be variable. The longer the period you compare the more accurate you should be able to get this fine tuning.