Why One-Size-Fits-All IAQ Does Not Work
Many families buy one large air purifier for the living room and consider the job done. In reality:
- Kitchen: UFP from frying can be 100x higher than outdoor levels during cooking
- Child’s bedroom: dust mites in bedding, CO2 accumulation overnight
- Living room: PM2.5 from outside, VOCs from furniture
- Home office: CO2 buildup from seated work directly impacts concentration
Good IAQ design requires analyzing the specific pollution sources in each room first.
Child’s Bedroom: Highest Priority
Children breathe 30-50% faster than adults and spend 8-10 hours/day in their bedroom. Main risks:
Dust Mites:
- Temperature 24-27°C + humidity > 60% RH = ideal dust mite conditions
- Solution: dust mite-proof mattress cover, reduce humidity below 55% RH
- Automation: dehumidifier turns on automatically when humidity > 60%
Overnight CO2:
- 15 m² closed bedroom can reach 2,000-3,000 ppm CO2 overnight
- Solution: fresh air supply from ERV or trickle vent at door
- Target: CO2 < 1,000 ppm throughout the night
Recommended equipment for children’s bedroom:
- HEPA H13 air purifier 200-300 CADR: Coway AP-1512HH
- CO2 + Humidity Sensor: Aranet4 or Aqara TVOC
- Night Mode: purifier fully silent (< 25 dB) during sleep hours
Kitchen: The UFP Battle
Frying food in hot oil produces UFPs (< 0.1 μm) that even HEPA H13 cannot fully capture. The correct approach:
An Effective Range Hood:
- Must move ≥ 600 CFM for a 4-burner stove
- Use baffle filter instead of mesh (easier cleaning, better capture)
- Smart plug + power monitor: when range hood runs → open makeup air damper
Smart Kitchen Automation:
yaml
alias: "Kitchen Cooking Mode"
trigger:
- platform: numeric_state
entity_id: sensor.kitchen_pm25
above: 50
action:
- service: switch.turn_on
target:
entity_id: switch.range_hood_boost
- service: fan.turn_on
target:
entity_id: fan.kitchen_exhaust
Do not use an air purifier in the kitchen: purifiers recirculate air. With extremely high UFP levels, the filter clogs quickly and cannot fully capture sub-micron particles. The correct strategy is exhaust and dilute, not recirculate.
Living Room: PM2.5 and VOC Management
The living room receives both PM2.5 infiltrating from outside and VOCs off-gassing from new furniture:
PM2.5 Season Mode (November-April):
- HEPA H13 air purifier full speed: Winix C545 or Blueair Blue Pure 311i
- Door sweep on all exterior doors reduces infiltration 40-60%
- Monitor outdoor AQI via IQAir/AirVisual API into HA
New Furniture VOC Off-gassing:
- New furniture releases formaldehyde for 2-4 weeks
- Automation: TVOC Sensor > 400 ppb → ERV fresh air at 100% speed + alert to open windows
Home Office: CO2 and Productivity
CO2 and Cognitive Performance:
- < 800 ppm: Excellent focus
- 800-1,000 ppm: Slight reduction
- 1,000-1,400 ppm: Significant impact (-21%, Harvard Study)
1,400 ppm: Poor performance
Home office automation:
- CO2 > 1,000 ppm → activate ERV Boost Mode + suggest a walking break
- CO2 > 1,400 ppm → LINE alert: high CO2, please open window or step outside for 10 minutes
IAQ Dashboard: Whole-Home View on One Screen
HA family IAQ dashboard:
- Grid view showing every room: PM2.5, CO2, humidity, temperature in real time
- Color coding: green (good), yellow (caution), red (unhealthy)
- Alert history: log every IAQ threshold exceedance
- Weekly IAQ report: LINE message every Monday summarizing hours of good air in each room
Summary: Good IAQ Is Long-Term Health Investment
Per-room IAQ design costs little more than buying one large air purifier, yet delivers significantly better health outcomes — especially for families with young children or allergy sufferers.