Yes, I did read the article. Would it not be warmer in southern UK than northern?
As it applies directly to US:
The most expensive homes in America - Forbes.com - MSNBC.com
Your point is that it has to do with building materials as it applies to temperatures which I would imagine also has to do with weather. Weather is extreme in areas of the south as well. If you live where there are frequent hurricanes, I would imagine, based on your argument, that there might be different building materials used in the form of reinforced concrete, windows roof etc. Perhaps more expensive materials for that matter than we use here.
N, S, E, W, I don't care what you want to call it. Your comment had to do with temperature and less to do with the South. My point, if there is a difference, is socioeconomic and nothing to do with building materials/weather.