Environmental controls were installed throughout the galleries of the Wallace Collection in the 1980s, principally in order to protect the Collection's important but vulnerable veneered furniture.
Wood veneers, and those of turtleshell and brass (Boulle marquetry), are particularly prone to expansion and contraction arising from fluctuations in temperature and humidity, causing the veneers to buckle and lift.
Today, the gallery air-conditioning system is overseen and operated by a specialist maintenance contract team which provides a daily on-site service maintaining heating, cooling, humidification, insulation, lighting and drainage within the building. The overall aim is to maintain the gallery temperature throughout the year at about 20 degrees centigrade with a relative humidity level of around 55%. This is accomplished by means of two plant-rooms, one on the lower ground floor (maintaining a stable level of temperature and humidity throughout the ground floor galleries) and another on the second floor doing the same for the first-floor galleries.
Air filters help to reduce dust and particulate dirt levels throughout the Collection. In the early 1900s the polluted London atmosphere resulted in most of the paintings having to be glazed to protect them, but today the air circulating within the galleries is sufficiently clean that virtually all this glass has now been removed.