There are a a couple indications you should have house ventilation, including:
1. Ever-present odors
If you have problems getting potent aromas out of your space, you might have a ventilation concern.
2. Stuffy air
The air in your house should be fresh, but musty sectors mean you likely have inadequate ventilation.
3. Lots of dust
Dust can develop more rapidly in homes with inadequate airflow.