I live in a 160m2 (1700 sqft) house in Northern Europe (54N). 10kWp of solar on my roof generates around 1/3 more than I consume over the year. Everything is electric, I don't have natural gas. I have a heat pump for heating and cooling (rarely gets above 30c here). If I had a battery April - September could all be local consumption (I pull around 5kWh from the grid each day).

The issue is winter: It gets down to -25c and there is very little sun (not that it would help due to snow on the panels). In January and February this year I generated a grand total of 5kWh :D

However my house is a new house, it's designed to modern building standards and has 30cm of PIR insulation in the walls and even more in the roof. There's just no way to properly renovate old buildings to be like that without basically rebuilding the whole thing. The actual cost of materials is not expensive though (for the west). In milder climates (UK I'm looking at you) there's really no reason all new houses cannot be net-zero.