Ventilation—the exchange of indoor and outdoor air—is fundamental to indoor air quality. More ventilation generally means lower concentrations of indoor pollutants. But in apartments, you often have limited control.
Why Ventilation Matters
Without adequate ventilation:
- CO2 from breathing accumulates (causing stuffiness)
- VOCs from products and materials concentrate
- Humidity from cooking and bathing builds up
- Odors persist longer
- Indoor pollutants have nowhere to go
Ventilation dilutes and removes these issues by bringing in fresh air and exhausting stale air.
Types of Ventilation
Natural Ventilation
Air exchange through windows, doors, and gaps in the building. Depends on weather, wind, and temperature differences.
Mechanical Ventilation
Fans that move air intentionally—bathroom exhaust fans, kitchen range hoods, and building-wide HVAC systems.
Infiltration
Unintentional air leakage through cracks and gaps. Can bring in outdoor pollutants along with fresh air.
What Renters Can Control
Windows
When outdoor air quality is good, opening windows provides free, effective ventilation. Cross-ventilation (windows on opposite sides) is most effective.
Exhaust Fans
- Bathroom fan: Run during and 15-30 minutes after showers
- Kitchen range hood: Run when cooking, especially for high-heat cooking
- Always use these: They're designed to remove moisture and pollutants
Window Fans
A simple window fan can significantly increase air exchange. One fan blowing out while a window is open on the other side creates effective circulation.
Ventilation vs Air Purification
These are different strategies:
| Ventilation | Air Purification |
|---|---|
| Exchanges indoor/outdoor air | Recirculates and filters indoor air |
| Removes gases (VOCs, CO2, odors) | Removes particles (HEPA) and some gases (carbon) |
| Affected by outdoor air quality | Works regardless of outdoor conditions |
| Affects temperature/humidity | No effect on temperature/humidity |
| Often free (windows) | Requires electricity and filter replacement |
They're complementary. Ventilation when outdoor air is good; purification when you need to keep windows closed.
When to Ventilate
Good Times
- Outdoor AQI is low (good air quality)
- Mild weather (not too hot or cold)
- During and after cooking
- After cleaning with chemical products
- When the space feels stuffy
Bad Times
- Wildfire smoke events
- High pollution days
- Peak pollen season (if allergic)
- Extreme temperatures
- When noise from outside is problematic
Building Ventilation Systems
Many apartments have central HVAC that provides some ventilation. As a renter:
- Keep vents clear and unblocked
- Report HVAC problems to management
- Ask about filter replacement schedules
- Note if air feels stuffy despite HVAC running (may indicate problems)
Improving Ventilation in Challenging Situations
No Windows
Some rooms (bathrooms, interior rooms) lack windows. Rely on exhaust fans and keep doors open when possible to allow air exchange with ventilated spaces.
One-Sided Apartment
With windows only on one side, cross-ventilation isn't possible. A window fan can help, or running bathroom exhaust while windows are open creates flow.
Noisy Location
If outdoor noise makes window ventilation impractical, rely more on mechanical ventilation (exhaust fans) and air purification.
The 5-Minute Flush
Even brief ventilation helps. Opening windows for 5-10 minutes when you wake up can clear overnight CO2 accumulation without significantly affecting indoor temperature. It's a quick reset for stuffy mornings.