Exactly.
I have one of the USB adapters @Bill.Thomson pointed to (from China IIRC) plugged into an OrangePi talking to a MHRV via a Python script. Assuming you don’t want your laptop tied to a plugged in adapter hardwired into your meter, you might be better looking at a Pi based solution possibly via Node-Red and pass the data to EmonCMS via HTTP or MQTT.
Absolutely and a link to get you started Read the SDM220 modbus with the minimalmodbus python module. 
I also found a node-red flow although this is for an SDM120