But any modern house is too airtight and essentially requires ERV.

Which brings us to next interesting problem - you would think that ERV should be built-in into modern cooling/heating systems, but it’s no the case.

Yes, it's one of the cheapest way to reduce your energy needs and have clean air, plus it's fairly low tech system

ERV = Energy Recovery Ventilator

Also, they usually hook up the interior air intakes to bathrooms so smells and extra humidity have a constant flow out of your house.