Revisions log for question
Is primary ventilation necessary in a detached house?

We are building a single family home and have installed a controlled mechanical ventilation system.

There are three bathrooms in the house, two on the second floor and one on the first floor. The upper floors each have different downspouts because one is at one end and the other at the other, one of them shares a downspout with the kitchen. The first floor bathroom has a horizontal downspout (manifold).

Is primary ventilation necessary in all the bathrooms? The architects say it's not necessary, but it's not entirely clear to me.

• bathroom
• ventilation