The Museum holds collections numbering about 3.5 million objects, which include artefacts related to Natural History, Geology, Archaeology, Social History, Costumes and Textiles, Photography, Literature, Fine Art, Decorative and Applied Art. It owns and displays several unique collections of international importance, including a significant geology collection from the UNESCO Jurassic Coast World Heritage Site and a Thomas Hardy Archive recognised for its worth on the UNESCO Memory of the World register. The Museum also houses an extensive library and archive and has an active temporary exhibitions programme in partnership with national museums and regional partners.  

The broad variety of materials and media held in the collections means there is a need for a wide range of environmental requirements. From an early stage Skelly & Couch engaged with the museum to help define a brief for the environmental control in each space. The process involved finding a balance between the need for comfort and conservation of artefacts and capital and running costs, and applying recent research which suggests that maintaining stable conditions with some seasonal variation in temperature and humidity is acceptable in museums, provided rapid changes and certain extremes are limited. 

The archives in the basement will be controlled using passive measures such as a highly insulated fabric, high thermal mass and hygroscopic building materials.  The gallery spaces and workrooms shall be controlled using a range of Heating, Ventilation and Air Conditioning Equipment, from natural ventilation to full air conditioning.