There are a a couple warning signs you should have house ventilation, including:
1. Ever-present odors
If you have trouble getting intense smells out of your house, you could have a ventilation issue.
2. Stuffy air
The air in your rooms should be fresh, but stale areas mean you could have issues with ventilation.
3. Disproportionate dust
Dust can build up more often in homes with insufficient ventilation.