This project consisted in investigating the cause of excess of humidity and recommend solutions. The complex is a multi-residential unit building. We did a site survey and did some fresh air calculation. We found out the reasons and provided a full report showing our findings. In this case the ventilation system in the units was not turned on because the occupants found the system noisy. The envelop seemed to have been poorly built which allowed cold air to leak in and cause condensation and frost. Our recommendations included a building envelop thermal analysis. In this case any amount of humidity would travel from hot areas to cold ones thus creating frost on windows where the surface temperature would be lower than the dewpoint. Ecovision recommended the use of ventilation heat exchanger with low decibels for comfort and this technology lowers energy bills.