How to get rid of negative air pressure?

To get rid of negative air pressure in your house, you need to balance exhaust and supply air and provide makeup air for devices that pull air out. First, identify major exhaust sources, high-CFM kitchen range hoods, bathroom exhaust fans, clothes dryers, central vacuums, and fireplaces that consume combustion air. Avoid running all of them at once, and when you use a powerful range hood over 400 CFM, crack a window nearby to provide immediate makeup air. For a permanent fix, install an interlocked makeup air system that automatically brings in outside filtered air when the range hood operates, which is now required by building code in many places for large hoods. Have an HVAC professional seal leaky return ducts located in attics or crawlspaces that can pull air from unconditioned spaces and create negative pressure in living areas. Ensure your HVAC system has balanced supply and return airflow. Consider adding a fresh air intake, energy recovery ventilator or heat recovery ventilator that supplies filtered outside air while saving energy. For fireplaces, install an outside air kit for combustion so it does not suck house air. Check that exhaust fan dampers are not stuck open. You can test with a tissue at a slightly open door, if it pulls inward strongly, you have negative pressure. Also install carbon monoxide detectors because excessive negative pressure can cause backdrafting of furnaces and water heaters, which is dangerous and needs immediate professional correction.