Multifunction Mechanical Systems

The document assesses three types of multifunction mechanical systems designed to reduce the cost and disruption of building decarbonization retrofits in multifamily housing. It examines fully packaged systems (e.g., Systemair Genius), partially packaged systems (e.g., Villara AquaThermAire), and distributed systems (e.g., Ephoca AIO WM paired with SanCO2), focusing on their ability to integrate heating, cooling, ventilation, and domestic hot water (DHW) using low global warming potential refrigerants.

• Fully packaged systems, such as the Systemair Genius, integrate heating, cooling, domestic hot water (DHW), and energy recovery ventilation (ERV) into a single enclosure approximately 3’ x 3’ x 7’ tall, utilizing R32 refrigerant and a single 40A, 240V electrical connection.
• Partially packaged systems, exemplified by the Villara AquaThermAire (AQTA) using R454b refrigerant, combine heating, cooling, and DHW with one compressor. The AQTA features a unique defrost cycle that uses heat stored in the hot water tank to defrost the coil, preventing the discharge of cold air into heated spaces and shortening cycles to two to three minutes.
• Distributed systems utilize room-by-room through-wall equipment for space conditioning and ventilation, paired with separate water heating. For example, the Ephoca AIO WM+ERV (using R32) provides ductless heating, cooling, and ERV, while the SanCO2 system (using R744) provides centralized hot water via an inverter-driven heat pump and 119-gallon storage tanks.
• The primary goal of these multifunction systems is to overcome barriers to building decarbonization by reducing the extensive, costly, and disruptive building modifications typically required to install replacement HVAC and DHW technologies.

APA

RMI (2025). Multifunction Mechanical Systems. https://rmi.org/resources/multifunction-mechanical-systems/

Chicago

RMI. Multifunction Mechanical Systems. 2025. https://rmi.org/resources/multifunction-mechanical-systems/.

Wikipedia

{{cite report |author=RMI |title=Multifunction Mechanical Systems |date=15 April 2025 |url=https://rmi.org/resources/multifunction-mechanical-systems/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2025multifunction, author = {{RMI}}, title = {{Multifunction Mechanical Systems}}, institution = {RMI}, year = {2025}, month = apr, url = {https://rmi.org/resources/multifunction-mechanical-systems/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }