Stone Mountain Technologies’ gas absorption heat pumps (GAHP) are drawing the attention of propane industry leaders who are intrigued by how the technology can position LPG in its ongoing battle with electrical equipment.
In fact, the National Propane Gas Association (NPGA) shared information about the company and its heating technologies during the association’s fall board and committee meetings in Burlington, Vermont.
NPGA’s members include small businesses and large corporations engaged in the retail marketing of propane. More than half of all retail propane gallons sold in the United States go toward residential applications, most of which are for space heating. In 2024, the residential market totaled about 4.7 billion gallons in propane sales, according to a report by Frost & Sullivan on behalf of the Propane Education & Research Council (PERC), the other U.S. propane organization.
Stone Mountain’s 80,000-Btu Anesi gas heat pumps, fueled by propane or natural gas, leverage combustion heat to capture additional energy from the outdoor air. While the thermal process offers many advantages, heat pump efficiency and performance are the focal points for NPGA officials.
NPGA cites the heat pumps’ AFUE rating of up to 140% and their coefficient of performance of 1.43. These ratings give Stone Mountain’s gas heat pumps a significant advantage over other equipment currently on the market, including that of electricity, according to NPGA.
“When you hear ‘heat pump,’ automatically everybody thinks of electric, and that’s not necessarily the case,” says Bert Warner, director of commercial business development for PERC. “Some of the challenges of electric heat pumps are the strong suit of a gas heat pump.”
Stone Mountain’s gas heat pumps thrive in cool and cold climates, making them especially valuable to homeowners in the northern United States or throughout Canada. Whereas electric heat pumps often require sufficient backup systems to satisfy homeowners’ heating needs when temperatures drop, the gas heat pumps, manufactured by Stone Mountain in Piney Flats, Tennessee, provide customers with the desired comfort at lower operating costs compared to electricity.
“In the majority of the markets in the U.S., there’s really not a need for a backup [to the gas heat pump],” Warner says. “It is its own backup because it is able to perform at such low ambient temperatures and still retain good efficiencies at those low temperatures, where an electric system is going to need something different when you get to negative degree-days.
“To me, that’s a key element,” he adds. “They can perform in any climate and at good efficiencies.”
In addition to serving the residential market, whether in retrofits or new construction, Stone Mountain and its gas heat pumps offer versatility by performing in the commercial water heating space as well.
NPGA took notice of the company’s GAHP system for water heating in commercial buildings, again with the technology boasting up to the same 140% efficiency performance as the single-family residential units. The national association is also considering the potential opportunities with Stone Mountain’s Heat-Chain product, which is newly available on the market.
The Heat-Chain allows for two or three skid-mounted models to team on a specific application, as it also simplifies transport, installation and scaling.
“We’re always looking for technologies that can use propane,” Warner says. “The nice thing about [Stone Mountain], it’s not just comfort heating – it’s also the water heating. Hot water is a necessity everywhere. The fact that you’re able to do that with a propane product at efficiencies well above 100 percent is almost unheard of. “Most gas products, you can’t break that 100 plateau,” he says. “Stone Mountain lives above that plateau.”