The London Library is the world’s largest private subscription library, holding approximately 1.5 million books. The historic library spreads across five different Grade II listed buildings and a 1970s office block. 

Building fabric changes and air movement improvements achieved the fundamental objective of improving environmental conditions for the books, while maximising storage space.

While full temperature and humidity control and carbon filtration was provided for the rare book collection, the remaining stacks used a more passive solution. Environmental conditions were controlled by correcting seals, improving insulation and avoiding light penetration with assistance from mechanical ventilation.