> there is a strong emphasis on air tightness and insulation now. Which isn't exactly great without heat recovery ventilation. Either you open the windows to g

> there is a strong emphasis on air tightness and insulation now. Which isn't exactly great without heat recovery ventilation. Either you open the windows to get fresh/non-humid air and lose your heat, or you end up with condensation spots from lack of ventilation. Particularly with modern houses lacking outdoor space in which to dry your clothes... Besides, most of the tightness and insulation can be fairly easily retrofitted to older houses. It does get harder pre-1930 where they use solid wall construction, but 1950 on isn't too hard to bring up to modern standards. Double glazing, cavity and loft insulation, new tightly fitted windows and you're mostly there.