Energy impacts of air leakage in US office buildings.

Airtightness and infiltration rate measurements in office and other commercial buildings have shown that these buildings can experience significant levels of air leakage [1,2]. The energy impact of air leakage in U.S. office buildings was estimated based on the analysis of a set of 25 buildings used in previous studies of energy consumption [3,4]. Each of these buildings represents a portion of the U.S. office building stock as of 1995. The energy impact of air leakage in each building was estimated by performing an hourly analysis over one year, with the infiltration rates varying linearly with the wind speed. The energy associated with each of the 25 buildings was then summed to estimate the national energy cost of air leakage. The results show that infiltration accounts for roughly 15% of the heating load in all office buildings nationwide, and a higher percentage in recently constructed buildings. A sensitivity analysis showed that the heating loads due to infiltration were particularly sensitive to uncertainty in the balance point temp-erature and nigkittime thermostat setback. The results also show that infiltration has very little impact on cooling loads in office buildings. The results for office buildings are presented and discussed, along with the implications for the energy impacts of air leakage for the total commercial building stock in the U.S.