From normal use calculated from monthly use, a 5kW inverter is sufficient. But since I have 3 old school fridge/freezers, I am afraid that peak power use might be more.

I need to measure possible peak usage. Is it possible to hire a meter somewhere, or how is this usually done?

6 hours ago, Brani said:

Effergy meter will record your peak power.

But I found it limiting as it just showed me the highest peak ever. 
If you monitor it regularly, you can get a very good idea of what your highs are.

 

I think this is where the efergy hub beats out the classic as you have real time online analysis. 

Thank you, I enjoyed the read..haha

I decided to go for the 8kW Sunsync instead of the 5, just to give me room for upgrade. Future might install fencing and pool heatpump.