I live in Northern Europe where houses are built like this, and a 160m2 (1600sqft) house is typically fitted with a 8kW-12kW heat pump (heat output, so input electricity is 3x less) - which is used for hot water too.
That may sound low, but the thing is houses here are very well insulated, so when you heat the masonry walls and floors to 21c it takes a very long time for the temperature to drop - the heat pump is just maintaining the heat
We live in a slightly older house (which doesn't meet current insulation standards) and last year the heat consumption was 70kWh per m2. That's for heating and hot water.
That may sound low, but the thing is houses here are very well insulated, so when you heat the masonry walls and floors to 21c it takes a very long time for the temperature to drop - the heat pump is just maintaining the heat
We live in a slightly older house (which doesn't meet current insulation standards) and last year the heat consumption was 70kWh per m2. That's for heating and hot water.