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Dylan Ingui
High School Student - Passive House Enthusiast
Asked a question 2 years ago

I have heard and seen some examples of multifamily homes that are certified as passive before, but I don't completely understand how the ventilation for these types of buildings work. Are there good multifamily units out there already or have people just been installing an hrv/erv for every given apartment/home? Also, how do people typically go about making the decision of what type of unit to use?

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Hi Dylan, the answer to your question really depends on a bunch of factors.  There's three main ways to handle ventilation in a multi-family building; Decentralized (one ERV/HRV in every unit). Semi-Centralized (one ERV/HRV per floor or block of units). Or Centralized (one ERV/HRV for the building).  A building with condos might choose to have a completely decentralized ventilation system so that every unit owner maintains their individual ERV/HRV (filters must be cleaned 3-4 times per year).  If the building is full of rental units, the building owner may not want to clean all of those filters and may opt for a semi centralized or centralized system to cut down on maintenance.  However, there are other things to consider as well like who pays the electric to run the ventilation system?  Or what is the strategy for running ductwork and installing smoke and radiation dampers?  Answers to those questions (and others) also influence what type of system gets installed.  I've worked on projects using all three types of systems and there is no one right answer for all projects.  It is really important for the building owner and operators to understand the ramifications of the different design options though because systems, which are typically not seen (ventilation especially) have a very big influence on what is seen (architecture), especially in multi-family passive houses.