FilterEasy, a US-based subscription service for heating, ventilation and air conditioning (HVAC) filters, raised $6.9m in a series B round on Tuesday from investors including North Carolina State University’s endowment fund.

NC State Endowment Fund participated alongside Arsenal Venture Partners, which led the round, Bonaventure Capital, Cofounders Capital, Idea Fund Partners, Triangle Angel Partners  and John Replogle.

Founded in 2013, FilterEasy offers HVAC air filters on a subscription basis, regularly delivering filters in the required size to customers. Replacing the…