HRVs should be located inside the conditioned space in cold climates. WI attics are cold and cause condensation inside the ducts containing damp house air. Basement is much better than the attic unless atttic is warm during cold weather.
Exhaust stale air from the center of high spots inside the home like largest bath. Fresh air is cool after flowing through the HRV and should be mixed with house air befor distributing the fresh air throught the home. A little cool air supplied high in the conditioned space throughout the home is not noticiable. Regards TB
Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
Use +Merv 10 air filter. -Don't forget the "Golden Rule"