Describes an award-winning retrofit project for the London (Ontario) Regional Art and Historical Museum, an 88,000ft² (8175m²) building housing more than 20,000 artefacts. The complex is served by five cooling-only air handling systems that previously utilised only minimum outdoor air ducting and terminal reheat coils for heating. Before the retrofit, a 136 kW electric steam boiler provided humidification to each air handler. Two reciprocating chillers provide the cooling requirements. Describes how the retrofit was designed to improve and stabilise space conditions to meet critical standards for museums, to minimise energy consumption and reduced operating budgets, minimise maintenance costs and increase operator efficiency while not detracting from aesthetics. States that in the first full year of operation the retrofits achieved energy savings of $154,000 and electrical consumption savings of 2.8 million kWh/yr, with additional lighting energy savings in the next year (1996).