Insulation can be orthogonal to fresh air. Ventilation energy recovery units [1] exist to help reduce loss from fresh air (and are code for new houses where I am). This has the benefit that you can have more fresh air, for the same heat loss, since the loss will be from the fresh air, rather than through high thermal conductivity through the non-breathable portions of the walls.

1. https://en.wikipedia.org/wiki/Energy_recovery_ventilation