"I designed this room to be completely undetectable. It's covered in enough wards that she could cast a thousand Homenum Revelios and never know we were here. It's soundproof as well. No one can hear anything inside this room if they're outside of it and no one inside of it can hear what happens outside unless they're standing right here with the window open. Why else do you think I haven't been terribly concerned whether or not our son could hear us in our bedroom downstairs?"