Whole house hepa system, UV lights in ductwork, electronic air cleaners that are cleaned regularly, sealed filter housings on returns with high quality filters changed monthly,
Keep the dirt/dust off the evap coil so mold won’t grow on the dirt/dust during the cooling season.
May need periodic cleaning of the coil/fan wheel and housing if you get dirt/dust show up there.
The whole house hepa system(s) is the way to go. Pricey to start but a worthwhile investment.
Lastly controlling humidity so that mold has less chance to grow. Wood moisture content below 19%, humidity levels less than or equal to 55%.
Make sure duct systems are actually sealed with mastic and pass blower door tests.
Exhaust fans near showers that duct to outside, dryer vented to outside etc.
And don’t mix crawlspace air with house air.
If you have fresh air intakes on HVAC systems make sure it’s not pulling air at ground level near natural areas. Filter this air and change those filters regularly. Better to get this air from a porch ceiling or roof eave away from the ground.
If you control the moisture you control whether or not mold can grow.
If you control the dust/dirt in the areas that you can’t control the moisture (evap coil in AC unit) then mold will have no food source to grow.
Hepa will filter out mold spores but won’t stop mycotoxins.
Keep mold colonies small, dead, or dormant to prevent continual release of mycotoxins that try colonies release to fight other colonies.
We are caught in the crossfire of these mycotoxins from differing colonies.
