> Maybe give people free HVAC upgrades to filter more particles. HVAC and indoor air quality (IAQ) is a fascinating topic and it takes good design to get it ri

> Maybe give people free HVAC upgrades to filter more particles. HVAC and indoor air quality (IAQ) is a fascinating topic and it takes good design to get it right. In most HVAC systems you can't just stick a higher MERV filter in and expect good results because they are designed for specific amounts of air flow. Thicker filters cause more air resistance which reduces air flow and fan efficiency which means less comfort and greater energy use. Often a better strategy in a retrofit is to increase air sealing (a good energy recommendation anyway) and install an E/HRV to exchange indoor for outdoor air with a good filter in it. PM2.5 comes from outside so this should take care of it. https://www.energyvanguard.com/blog/unintended-consequences-high-merv-filters https://www.energyvanguard.com/blog/unintended-consequences-... https://www.energyvanguard.com/blog/7-reasons-your-filter-isnt-improving-your-indoor-air-quality https://www.energyvanguard.com/blog/7-reasons-your-filter-is...