Double Duct Packaged Terminal Heat Pump Field Demonstration

Many multifamily and light commercial buildings such as hotels use through-the-wall packaged terminal units as an affordable option for space heating and cooling. However, this product class is generally less efficient than other product types for distributed, ductless conditioning. A new type of packaged terminal heat pump with a more compact form factor and two small duct penetrations for outside air exchange is now available, possibly adding a premium efficiency option to this market niche.  Compared to past packaged terminal units, the “double duct packaged terminal heat pump” (DDPTHP) minimizes building envelope disruption, eliminates outside equipment, includes multi-speed and variable speed motors, eliminates electric resistance defrost, and can provide efficient, affordable electrification of heating. However, these efficiency benefits and product performance had not yet been previously validated. This project performed a field evaluation of the technology in four homes within a new construction, affordable housing multifamily building. The project team monitored equipment energy usage and loads for six months at each site and used the data to compare its performance to an equivalently sized code-minimum packaged terminal unit baseline. The emerging technology’s performance was quantified in terms of energy savings, cost-effectiveness, and other impacts with energy savings of five to forty-three percent. The project also acquired some basic user and stakeholder feedback that relates to installation and product usage. The emerging technology shows promise for convenient, affordable, and efficient electrified heating and cooling, including in retrofit scenarios. In parallel with other ongoing laboratory work, a modeling study of the technology should be done to establish savings across a range of California building types and climate zone conditions so that a rebate measure support workpaper can be established for heating and cooling efficiency and electrification programs.