SAN FRANCISCO — Gradient Comfort, a company built by thermal scientists to develop and build climate-friendlier HVAC products, has closed a follow-on round of funding that raised $9 million, bringing its total Series A funding to $27.5 million.

The round was led by Climate Investment (CI), a specialist decarbonization climate investor. Cindi Bough, managing director of ventures at CI, will join the Gradient Comfort board, and Rick Cutright, CI’s technology director, will join as an observer. 

Gradient Comfort is CI’s latest investment in the built-environment space. The firm currently has a number of investments in its built-environment portfolio, including 75F and Aeroseal. 

“It is essential that buildings have carbon-neutral solutions that are effective and affordable,” Bough said in a press release. “Heat pumps are increasingly recognized as a critical technology for buildings’ decarbonization. Innovations are needed to lower purchase and installation costs, reduce complex renovations, improve energy performance, and leverage heat pumps for (the) grid, and flexibility. We believe Gradient Comfort’s solution suite delivers on all of these elements.” 

According to the International Energy Agency, the number of heat pumps installed globally will increase from 180 million in 2020 to around 600 million in 2030. Heat pumps are at least three times more efficient than traditional fossil-fuel boilers; the installation of heat pumps in individual buildings is expected to increase from 1.5 million per month currently to around 5 million a month by 2030.

According to the Air Conditioning, Heating, and Refrigeration Institute, U.S. heat pump sales rose above 4 million units for the first time in 2022, outpacing the sale of gas-fueled furnaces.

HVAC is a major contributor to greenhouse gases, due to commonly used refrigerants and the use of heating oil and natural gas.

Gradient Comfort’s first product, the Gradient, is a window-mounted heat pump that uses a climate-friendlier refrigerant (R32) and does not block the view from a window. 

Gradient Comfort will leverage the new capital in several ways, including:

• To deploy Gradient Comfort’s air-sourced window heat-pump units, which decarbonize heating for cold climates and deliver air conditioning with R32 refrigerant.

• To accelerate decarbonization with a focus on solutions for business-to-business channels

• To access software services like hardware monitoring, maintenance, leasing, and demand-response services, including integration with virtual power plants.

• To add personnel in key roles.

“We are reimagining the HVAC industry by building products that keep homes comfortable and healthy for the people who inhabit them, without compromising the environment,” said Vince Romanin, Gradient Comfort co-founder and CEO. “Support from Climate Investment will enable us to expand our operations, build new products, and achieve a 95% carbon reduction when our products are used to both heat and cool.”