There are a a couple signs you should look into house ventilation, such as:
1. Ever-present odors
If you have trouble getting potent smells out of your house, you could have a ventilation concern.
2. Stuffy air
The air in your rooms should be fresh, but stuffy areas mean you may have poor ventilation.
3. Lots of dust
Dust can develop more frequently in rooms with stifled ventilation.