do you have a model I can look at? auckland used to be a bit dryer but in the last couple of years starting to get 85%+ humidity in both summer and winter and get foggy randomly.. the houses around here weren't built for this type of weather. I've seen some hrv systems like lossnay from mitsubishi but i don't think it deals with incoming humidity at all, it is probably relying on indoor heatpumps to deal with it. not even a drain from heat exchanger