The heating installation service secured its second investment from E.ON as Rocket Internet and Holtzbrinck Ventures joined its pool of backers.

Thermondo, a Germany-based digital heating installation service, secured €6m ($6.4m) yesterday in a series B round featuring energy company E.ON and internet holding company Rocket Internet.

Holtzbrinck Ventures, the venture firm spun out from publishing company Georg von Holztbrinck, led the round, and IBB Beteiligungsgesellschaft and Grey Corp also contributed capital.

Thermondo’s app connects heating equipment manufacturers and wholesalers with customers, simplifying the ordering process and collecting all relevant information for installers.

E.ON first invested in Thermondo in September 2014,…