How did you build a positive pressure system in your house?

To folks who’ve done it - could you detail how you created a positive pressure system inside your house? Where I live, I can’t find any HVAC professionals even familiar with that (or they think it’s only for hospitals or commercial buildings). Any names of parts used or an outline of how you installed it in your home would be much appreciated.

A few important pointers:

  • make sure your house is relative air tight and close any gaps with weatherstrips. Otherwise you need to built up a very strong pressure.

  • the fan must be build to provide pressure rather than airflow. Normal fans like box fans are not build for pressure. Look more for duct fans.

  • the hepa filter needs to be of extremely good quality because the air needs to be completely filtered with one pass through (unlike air purifier filters that have constant recirculating).

  • your ducting and system needs to be completely sealed so that you avoid getting dirty air into after the filter stage. Especially the place where the filter sits needs to be completely sealed so that no air can bypass the filter.

Makes sense. Basically do you recommend getting air from the outside and pumping it through the HVAC duct system into every room? How do you usually monitor if a room is positively pressured or not?

If the room gets to ZERO, independent of outside pollution is a good indicator.

See the graphs in: Air Purifier vs. Positive Pressure Fresh Air System – an unfair Battle?