Life cycle assessment of residential ventilation units in a cold climate

The life cycle assessment (LCA) methodology is used in this paper to assess the environmental impacts of residential ventilation units over a 50 year life cycle in Finland. Quantifying the consumption of the energy and material resources during the life cycle permits the estimation of the harmful emissions into the environment (air, water and soil) and the potential changes in the environment (climate change, acidification and ozone production). Two different ventilation units are evaluated, both of which include air-to-air energy exchangers. The research demonstrates that a residential ventilation unit, with a function of providing 501/s of outdoor ventilation air, but not heating the air, has a net positive impact on the environment when it is equipped with a air-to-air energy exchanger with an effectiveness greater than 15%. The greater the effectiveness, the greater the positive impact on the environment. (C) 2004 Elsevier Ltd. All rights reserved.