I installed an ERV system in my very small and very old home. It was quite a bit of work, but nothing terribly difficult. Finding a suitable spot for the ERV unit was the biggest challenge: it is quite bulky and not silent, and you need to be able to route ducting to it from all over the house.

It's easily the favourite thing in my home. It filters the outdoor air, reducing pollen and mosquitoes. It keeps out excess moisture in summer. I don't have to open a window when it's cold. It automatically goes into overdrive after a particularly steamy shower. It's great.

Could you share which one you installed and under which circumstances? I'm running two mobile HEPA air filters; not very efficient nor very effective I'd assume.