On the energy item modern HVAC systems use a device called an ERV to greatly reduce energy loss to ventilation. No need to turn down the heat to get fresh air.

On the energy item modern HVAC systems use a device called an ERV to greatly reduce energy loss to ventilation. No need to turn down the heat to get fresh air. The thermal plume associated with each occupant makes the problem a bit easier too, in general stale air heads to the top of the room because it's warmer and more humid therefore less dense. Not a new idea and some good models to look at. https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://techxplore.com/news/2020-12-ventilation-easy-highly-effective-low-cost.html https://techxplore.com/news/2020-12-ventilation-easy-highly-... https://hackaday.com/2022/07/07/the-benefits-of-displacement-ventilation/ https://hackaday.com/2022/07/07/the-benefits-of-displacement...