Switching to LED lights (and reducing usage) is one example of low-hanging fruit that is easily achievable without affecting lifestyle much. The fat needs to be trimmed in all areas.

Yeah, did I mention "Highly isolated apartment buildings"? (I did ;)

In fact, there are apartments here in Amsterdam that stay a cool 20C in winter with little or no heating at all, just the warmth from the water boiler flue running through the heat exchanger of the air ventilator.

Nationally sponsored infrastructure plans to replace existing buildings with energy class A at scale would put a big dent on energy consumption.