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    Pressurization Testing, Infiltration Reduction, and Energy Savings

    Published: Jan 1986

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    House tightening has become an important component of residential energy conservation programs. The technique of pressurization as a means of improving the effectiveness and labor productivity of house tightening has been increasingly used. It would be desirable if the measurements taken as part of the house pressurization activity could be used to quantify the degree of tightening actually accomplished. Such measurements were taken both immediately before and immediately after a house tightening activity carried out, as part of the Modular Retrofit Experiment (MRE), in 98 single-family houses in seven sites in New Jersey and New York. We have reduced the pressurization data from 55 homes according to two prescriptions, one rooted in the airflows actually observed at a relatively high pressure (50 Pa) and one requiring the extrapolation to a low pressure (4 Pa) by means of a curve fit through and beyond the observations. The two prescriptions turn out to give very different answers to the question: By what percent has the average air infiltration rate been reduced? In a large fraction of cases, the process of house tightening leaves a signature in the pressurization data such that the percent reduction in airflow is greater at lower pressures; as a consequence, the prescription which involves extrapolating to 4 Pa gives much larger estimates of the percent reduction in air infiltration achieved by the tightening process. In the seven sites we examined, the estimated percentage savings for the 4-Pa extrapolation was over twice as large on the average. The differences in the interpretation of pressurization data also lead to wide discrepancies in the expected reduction in naturally induced air infiltration, which was not measured in the MRE. In a subsequent experiment, known as the Dual Infiltration Reduction Experiment (DIRE), tracer gas decay measurements before and after house tightening supplement pressurization data. This experiment helps to clarify the relationship between air leakage reduction as measured by the two techniques—an area that has not been explored in past research relating natural air infiltration and leakage reduction pressurization.

    The natural air infiltration reduction can be interpreted directly in terms of energy savings. For the MRE houses, the air infiltration energy savings component is computed from estimates of natural air infiltration reduction. This component is compared woth total savings in space heating energy use where available utility billing data permit the latter to be calculated.


    Air infiltration, air leakage, blower door, tracer gas decay, pressurization

    Author Information:

    Jacobson, DI
    Graduate student, University of Illinois, Urbana, IL

    Dutt, GS
    Research fellow, University Nat. Auton., Mexico, D.F.

    Socolow, RH
    Research fellow, University Nat. Auton., Mexico, D.F.

    Committee/Subcommittee: E06.41

    DOI: 10.1520/STP19650S