Sweaty new-builds with no air con

We're slowly getting there. MVHC imo is going to be the next big one that goes in the regulations.
The concept is, you seal the house up so that airflow doesn't happen unless you want it to.
Then set up heat exchangers with ducting between the rooms.
So fresh air can be brought in, cooled/heated by the stale air going out.
And it also lends itself well to aircon systems.

There is also Part O of the building regs, which uses calculated shade on south-facing windows to minimise solar gain in the hottest months.