Well double and triple glazing, usually with coatings to minimise solar heating are readily enough available. A lot of the rest of the magic comes from old app

Well double and triple glazing, usually with coatings to minimise solar heating are readily enough available. A lot of the rest of the magic comes from old approaches found in most regions before we had cheap heating and cooling that encouraged cheap building that paid no heed to locale. Usually working with the local environment - to encourage shade, cooling, airflow, or to retain heat. Simple stuff like solar chimneys, windcatchers, or for cooler areas encouraging a greenhouse effect, far removed from full blown passive houses. Most of which can benefit from modern materials and controls, and be combined with aircon and central heating to achieve comfort for a lot less fuel.