If open foyer means what I think it means, an open foyer is pretty crazy.

Lots (most?) of 2 story US homes built in the last few decades have 20ft+ tall foyers or living room vaunted ceilings. Extremely inefficient for heating and cooling, especially since almost all have only 1 zone air conditioning.

https://www.homestratosphere.com/wp-content/uploads/2019/02/...

https://www.pinterest.com/pin/two-story-foyer-design-ideas-p...

We have a small, >4mi/kWh EV, the heating / cooking is all electric, and the house is small and extremely energy efficient by US standards.

Our panels produce 2000-3000 kWh per month in the summer, which is when we actually hit 2MWh of usage.

In California I assumed open foyer means literally open to the elements.

I should have been clearer and written foyer with tall ceilings where air flows freely between the top and bottom floor of the house.