I've lived for 8yr now in a home with a Zehnder HRV. It has mostly worked well, though recent wildfires were too much for its MERV-13 filters, forcing me to run

I've lived for 8yr now in a home with a Zehnder HRV. It has mostly worked well, though recent wildfires were too much for its MERV-13 filters, forcing me to run it at the very slowest speed and use air purifiers.