Home technology expert, Ross Trethewey teaches how air filtration systems work and how to build a localized DIY air filter. Ross explains the MERV air filtration system. MERV stands for Minimal Efficiency Reporting Value, a value that measures how effectively a filter stops particulates of varying sizes from passing through and into the air system. The higher the rating, the more effective the filter is at capturing smaller particles. The scale ranges from 1-16; in general, houses usually have around a MERV 5-12 system. Anything above MERV 16 is considered in the range of HEPA filters, those are used in hospitals and laboratories. Ross clarifies that homeowners cannot just install a MERV 16 or HEPA filter into the HVAC systems in their homes. In many circumstances the HVAC systems homeowners have in place simply aren’t strong enough to handle higher rated filters, as the higher the filter rating, the more resistance the HVAC system has to overcome. Even if you were to get a thicker filter that increases surface area, meaning less resistance, you’ll have to check if your HVAC system has enough space to install a thicker filter. Check with an HVAC technician to check what rating your system can handle. If you are unable to acquire a higher rated filter, Ross demonstrates how to build your own DIY air filter. By taking four MERV-13 air filters and duct taping them on all four sides of a box fan, you’ll have a localized air filter for any room you want. For about $100, you can have a little piece of mind during wildfires and other disasters that impact our air quality. https://www.youtube.com/user/thisoldhouse