Comparison of airtightness, IAQ and power consumption before and after air-sealing of high-rise residential buildings.

Air infiltration and ventilation has a profound influence on both the internal environment and on the energy needs of buildings. In most electrically heated high-rise residential buildings, in cold climates, during the peak winter conditions (below -18 deg C ambient temperature and above 15 km/hour wind velocity), the air infitration component contributes to heating load by 10 to 28 w/m2 - roughly 25 to 35% of peak heating demand. Any reduction in such uncontrolled air infiltration, without sacrificing indoor air quality, will have potential to reduce the peak heating demand. To evaluate the effectiveness of air-sealing measure, the air leakage rates through the building envelope were measured both before and after the air-sealing using the large vane-axial fan. Several air quality measurements (indoor temperatures, relative humidity, CO,, formaldehyde, radon gas) were taken in each building to assess the practical implications of air sealing on the indoor air quality and thermal comfort. The whole building airtightness tests showed that the air-sealing of the building envelope reduced the air leakage rate by 32% in one building and 38% in other. Energy monitoring for two buildings showed the reduction in heating demand by approximately 6 W/m2 of floor space -- 12 to 15% due to air leakage control. Indoor air quality tests showed that the air sealing had no negative impact on the general conditions of comfort and air quality in both buildings. The field implementation of air leakage control has helped to remove some of the uncertainties and shown the potentials for conservation are indeed considerable. This paper presents the field tests and results, and suggest a procedure for the use by air-sealing practitioners to evaluate different air-sealing strategies.