Gas Heat Pumps
In the mid-1990s, heat pumps fueled by natural gas instead of electricity were promoted as being one of the most advanced systems you could use to heat and cool your home. Most of the units installed went by the trade name of York's "Triathlon." While gas heat pumps had the electric heat pump's advantage of moving heat rather than generating heat, they had larger space requirements, plus higher first and maintenance costs. And with rising gas costs, they failed to produce the promised savings.
Although their features of variable speed drives that enabled them to provide more constant air flow, better humidity control and higher efficiency, other factors such as operating and maintenance costs, fewer qualified repair personnel resulting in questions of long term maintainability, and the environmental impact of internal combustion engine emissions all resulted in relatively low sales. So low that, despite gas industry promotion, the manufacturers could not justify remaining in the business and removed these gas heat pumps from the market.
Of course, most all of these features are also available on today's high efficiency electric heat pumps.