Heirloom uses the natural properties of limestone to remove carbon dioxide from the atmosphere and permanently store it. Heirloom heats the limestone in renewable-energy powered kilns to release the CO2, leaving behind calcium oxide that is spread on trays to act like a sponge and absorb more CO2 from the air. The captured CO2 is then extracted and stored securely underground or embedded in concrete.

Heirloom was co-founded in 2020 by Shashank Samala and Noah McQueen, who bring expertise in climate solutions and scaling technology companies. Samala previously worked at Carbon180 and co-founded Tempo Automation, a hardware company. McQueen has a background in chemical engineering research. The company has raised $54 million from top climate investors including Breakthrough Energy Ventures, Ahren Innovation Capital, and Lowercarbon Capital. Heirloom aims to remove 1 billion tons of CO2 from the atmosphere by 2035, equivalent to 10% of the annual global carbon removal needed by 2050.

The company is pioneering a highly scalable, low-cost approach to direct air capture. As the company opens its first commercial facility, it provides an opportunity to join a mission-driven team using innovative technology to address climate change. However, Heirloom will need to continue reducing costs and ensure its CO2 storage is permanent and environmentally safe as it scales to meet its ambitious removal targets.