Positive Pressure Ventilation: How It Works at Home
Positive-pressure ventilation supplies air into a home with a fan. The pressure difference can encourage air to leave through available paths. In aqi0’s whole-home air purifier, the outdoor supply passes through a pre-filter and H13 HEPA filtration before entering the home.
Follow the air path
The installation needs an outdoor intake, filtration, a fan, a supply route into the living space and routes for air to leave. The US Department of Energy describes supply ventilation as using a fan to pressurise the home, with air leaving through openings and other available paths. DOE whole-house ventilation overview.
This is an airflow principle, not a claim that every gap in every room always flows outward. Wind, open windows, exhaust fans, filter condition and room connections affect the result. Pressure and room conditions should be checked in the installed home.
Why the layout matters
A central supply needs a usable route to the rooms you occupy. During the assessment, discuss closed bedroom doors, multiple floors, kitchen and bathroom exhausts, and the places where outdoor air could enter untreated. Do not block exhausts to try to increase pressure.
For aqi0, one unit is intended for up to 2,000 sq ft of carpet area. Above that area or across multiple floors, plan for two units, with placement confirmed against the layout. Our technical note gives the sizing basis, including effective airflow of approximately 500 m³/h.
Filtration, ventilation and temperature have different jobs
HEPA filtration treats particles in the supply air. It does not mean all outdoor gases are removed. The intake location therefore matters, including nearby exhaust outlets and local pollution sources.
Outdoor-air supply also affects heat and moisture loads. aqi0 is not an air conditioner or a dehumidifier. DOE’s residential ventilation guidance notes that supply ventilation brings outdoor heat and moisture with it and does not remove indoor pollution at its source.
Keep appropriate kitchen and bathroom extraction. Positive pressure alone cannot guarantee that cooking odours will never spread.
What aqi0 currently installs
aqi0 installs a standalone filtered fresh-air system with its own intake and supply path. HVAC integration is not currently offered. The assessment considers how the installation will operate alongside existing cooling and exhaust equipment, without promising a connection to that equipment.
Verify the result
Check indoor PM2.5 under representative operating conditions and maintain the filters. Use a separate suitable CO₂ measurement when assessing ventilation; the optional aqi0 AQI/PM2.5 monitor does not measure CO₂.
The performance commitment sets out aqi0’s targets, operating conditions and remedies. Opening a window, changing occupancy or running a strong exhaust can change room conditions, so do not assume a universal recovery time.
Plan your installation
Have the carpet area, floor plan and normal room use ready. We confirm intake placement, supply routing, maintenance access and permissions for installation work with you.
Read the filter-care schedule and system pricing.
FAQ
How is positive pressure different from an air purifier?
A purifier filters air already inside the room. PPV brings in new outdoor air that has been filtered. PPV also lowers CO₂; purifiers don’t.
How much pressure are we talking about?
About 10–25 Pa. That is roughly the pressure exerted by one millimetre of water. You cannot feel it, but every leak in the home now flows outward.
Does it work with the AC on?
Yes. The AC recirculates room air for cooling; PPV brings in new air for breathing. They run in parallel.
Will my kitchen smells spread to the rest of the house?
No. Positive pressure plus an active kitchen exhaust means cooking air can only move toward the exhaust, not toward the living room.
What if I open a window?
The pressure equalises while the window is open and PPV’s protection is reduced. Within 30–40 minutes of closing the window, indoor air returns to a clean baseline.
Is the noise an issue?
A correctly sized aqi0 system at normal speed (4–5 V supply) is comparable to a ceiling fan on speed 2 — audible if you listen for it, not noticeable once you stop.