How bad it would be for air quality and exchange would come down to the HVAC almost entirely as long as the build quality is there. A modern energy efficient house is sealed so tight that the sum of all air leaks to the outside is smaller than a baseball.
The build quality would of course be the biggest concern, if they didn’t do the weatherproofing and water management right there would be water seepage and a high likelihood of a roof leak that would be horrendous to address.
How bad it would be for air quality and exchange would come down to the HVAC almost entirely as long as the build quality is there. A modern energy efficient house is sealed so tight that the sum of all air leaks to the outside is smaller than a baseball.
The build quality would of course be the biggest concern, if they didn’t do the weatherproofing and water management right there would be water seepage and a high likelihood of a roof leak that would be horrendous to address.