Thermal mass is not always a good thing. High thermal mass is helpful in a temperate climates where winter nights are chilly and summer days are warm, but the average temperature all year is comfortable.
We don't have that in most of America. Having a high thermal mass in New England just means your heater has to work harder in the winter to heat your thermally massive house. Ditto for Arizona during most of the year.
High thermal mass is very much desirable in Arizona. Adobe pueblos are used for traditional housing because they remain comfortable throughout summer without air conditioning due to the high thermal mass. A rug and some mild heating is sufficient to keep them tolerable even in extreme winters.
Insulation should absolutely be kept outside the vapor barrier and well ventilated for better performance, but thermal mass is less important than building super-airtight walls, with lots of insulation, good quality windows and controlled ventilation.
Was typically cold at night. I’ve lived in southern Arizona since the 90s. 30 years ago it would feel cool driving home from the city. Now? Not at all.
Owning a concrete block house feels like all my money is going through the walls. Even if you have the AC on in the summer, you can touch the walls from the inside and they feel warm. I’m definitely going to need to look at insulation going forward.
I think wood, stone, concrete and glass are all not great insulators, so that should be found in thickness, layering with different materials and airtightness (assumjng mechanical ventillation preferably with heat exhange). You can do that (and mess it up) with any of said materials.
We don't have that in most of America. Having a high thermal mass in New England just means your heater has to work harder in the winter to heat your thermally massive house. Ditto for Arizona during most of the year.