08/19/2026
Not every HVAC hack you see online is a good one.
Closing vents in unused rooms may actually restrict airflow. And when it comes to filters, “higher MERV” doesn’t automatically mean better if your system isn’t designed for it.
But one DIY idea that sounds questionable actually has some backing: a box fan paired with a MERV 13 filter can help reduce wildfire smoke particles indoors. Even the EPA has published guidance on this setup.
We broke down 3 popular HVAC hacks and what San Francisco homeowners should know before trying them ➡️
Which one have you heard before?