The Home Energy Meter allows you to measure your whole house electrical usage by placing the clamp in your circuit breaker.
The clamp will be placed on the incoming electricity cable that connects to the circuit breaker. It measures the flow of electricity through the cable based on magnetic flux.
Accordingly to Automate Asia, it is about 93% accurate. I am going to monitor it for a few months and compare it with my monthly electricity usage.
The Home Energy Meter is available in a number of configurations depending on whether you are using a 1 phase, 2 phase or 3 phase electricity.
In Singapore, most if not all homes are using a 1 phase electricity.
Installation is very easy. Remove the screws of the circuit breaker box and place the clamp on the brown wire. You just need to note the direction of the electrical flow of the clamp.
It is recommended to get an electrician to do the installation for you unless you know what you are doing.