Your request is very common, in the forum you will already find answers for example in this topic you use a very cheap energy meter connected in Modbus (You can use many all connected in daisy chain with RS485 connection to the CPU module).
In this topic we treat the DMX bus used to manage the dimming of the lamps.
In this topic we treat the acquisition of a true RMS value that could be the value in AC output from a CT.
By acquiring the pulse of the Enel meter with an optical transducer, you can calculate the instantaneous and total power (Topic, Topic). The meter can also be read via the IEC 62056-21 protocol but there are access passwords to activate the reading we use the protocol only on industrial meters (Topic).
In this topic find other ideas.
For the management of air conditioning from a look a this topic. I remember we have wall temperature sensors.