@ghettomaster Depending on your WiFi controller it may support Echonet Lite: https://www.mitsubishi-electric.co.nz/wifi/learn_echonet.aspx

Being a standard mainly used in Japan there are integrations for this and the standard is pretty well documented.

SJB:

 

How do you measure the actual output from a heat pump so as to enable a comparison with it's rated output?

 

You need to measure two things:

The airflow through the indoor unit. This will be difficult to measure accurately but you could get a rough idea by measuring the air velocity with an anemometer and averaging a number of readings across the exit, then multiplying by the cross sectional area. Multiply this number (the volume flow) by the density of air to get the mass flow.

The increase in temperature between the intake and exit of the indoor unit. 

Then plug into the formula: Q = m.cp.dT

Heat output (kW) = mass flow of air (kg/s) x specific heat capacity of air (kJ/kg.K) x increase in temperature (K)

https://adgefficiency.com/energy-basics-q-m-cp-dt/

SJB:

 

How do you measure the actual output from a heat pump so as to enable a comparison with it's rated output?

 

Easy. Is the room warm?

Thanks. Basically, not easy then.