A relatively new class of inverter driven mini-split heat pump or ductless heat pumps (DHPs) are capable of providing comfortable heating for a home when outdoor temperatures are as low as -15°F. These units are well suited for cold climates with little or no need for supplemental or backup heating. This document provides learning gathered from HVAC and building science professionals regarding optimizing performance and comfort when installing mini-split heat pump systems (DHPs, low-head “short ducted” and multi-head) in climates where winter temperatures commonly drop below 20 degrees Fahrenheit.
This document also provides guidance how to get the best performance and longevity out of a cold climate DHP. It also includes discussion of unique design considerations for multi-level homes, very low load homes, and air distribution in rooms without a heat source.
To help Northwest utilities more easily identify ductless systems that meet the Northwest Cold Climate Specification, NEEA has partnered with Northeast Energy Efficiency Partnerships (NEEP) to provide a pre-screened list of qualifying systems. NEEP maintains a cold climate air-source heat pump qualified products list, available on-line to search for variable-capacity heat pumps sold in North America with a COP ≥ 1.75 at 5°F as reported by the manufacturer. The list contains AHRI HSPF and SEER ratings and additional data on capacity and performance not typically found in general product literature.
Northwest utilities searching for only those systems that additionally meet the Northwest Specification of delivering ≥ 80% of rated capacity at 5°F can download a pre-filtered list through pre-approved access on Conduitnw.org. Please contact Suzi Asmus, NEEA Program Manager, to request access.