Installation of cold-climate heat pumps is increasing rapidly as states pursue decarbonization goals and homeowners recognize the environmental, health, and economic benefits of moving away from fossil fuels. Cold-climate heat pumps offer a huge degree of design flexibility; options for indoor units include high- and low-wall-mounted ductless heads, ceiling cassettes, and low-profile “compact-ducted” units. One design, in particular, has tremendous potential to scale: It is what many manufacturers refer to as the “multi-position air handler” or “vertical air handler.” These units (referred to as air handlers for the rest of this article) have a form factor—or hardware design—similar to a conventional natural gas or propane furnace. They can be installed in upflow, downflow, and horizontal configurations.
According to EIA data from 2015, about 53.8 million housing units in the U.S. have forced-air systems burning natural gas, propane, or fuel oil as their primary heating source. This represents about 79% of the housing units that use fossil fuel and about 46% of all housing units. Converting these furnaces to heat-pump air handlers presents a viable path to electrifying a large segment of our housing stock.
Advantages of air handlers over ductless minisplits
For homes with existing ductwork, air handlers are often the best choice. Compared to a strategy of putting ductless heads in multiple rooms, air handlers offer several advantages, including:
The ability to deliver heated and cooled air to every room. With ductless systems, it is usually cost-prohibitive to install a head in every room in the house. It is also a poor design strategy since even the smallest ductless heads can be oversized for small rooms. A typical ductless design leaves some rooms without their own source of heated and…
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