Demonstration of Mechanical Ventilation and Heating in Historic Buildings in Hot and Humid Regions

In late 1998, two historic buildings in hot and humid regions were selected for full-scale experiments on the use of humidistat-controlled mechanical ventilation and space heating. One was the Historic Archive in San Cristobal de La Laguna on Tenerife Island, Spain. The other was Hollybourne Cottage in the Jekyll Island Historic District on Jekyll Island, Georgia, USA.

The climate control systems consisted of sets of residential or industrial-type supply and exhaust fans and convection heaters, and were controlled by temperature and relative humidity sensors located inside and outside the buildings. To evaluate effectiveness, the climate and microbial activity were monitored in the buildings before and after the installation and operation of the climate control systems. Several different climate control designs were tested. Using either ventilation or heating, climates of the two historic buildings have maintained relative humidity levels safe from microbial attack (less than 70%). Reports on microbial monitoring also indicated a significant reduction in microbial activity.

Work Completed

  • Characterization of site climates and microclimates in the buildings through one year of environmental monitoring.
  • Laboratory tests of various fans and heaters, provided with antimicrobial filters, shutters and louvers.
  • Design of the mechanical ventilation systems for the two buildings.
  • Installation and operation of two systems in two historic buildings.
  • Evaluation of various control schemes and positioning of ventilators and heaters.
  • Application of simplified control devices for the climate controls.