Abstract
This manuscript explores the effectiveness of determining a building’s air changes per hour by monitoring indoor CO2 concentrations. Specifically, experiments involving the measure of infiltration and exfiltration were conducted using a NetAtmo indoor Weather-Station. The results of these experiments were then compared to the traditional method of blower-door tests. Through this comparison, the effectiveness of this new and easier method was determined. Using decay rates of tracer gases can significantly impact the cost, time, and frequency of measuring and quantifying a building’s efficiency. All measurements and data collected were on site at Sonoma State University’s Environmental Technology Center (ETC)
Introduction
Energy efficiency is at the forefront of building science. Buildings make up -- percent of the total energy use in America. A building envelope, whether effective or ineffective, is the physical separator between the inside and outside environment. A building’s ability to passively control the indoor climate is fundamentally linked to the temperature, energy efficiency, and air quality of the building. A successful building envelope is one that can generally maintain comfortable temperatures and high air quality. Ventilation rates serve as quantitative measure of a building’s envelope. Air-tightness can have positive and adverse effects. The blower door test is the current standard for measuring a building’s air changes per hour (ACH). This test requires specific equipment that requires some level of training. In addition to tetious equipment, the blower-door test requires a completely controlled system. Typically, it requires the building to be out of use. *Air Exchange rates. As an alternative to the blower door test, cheap and easy data loggers can incorporate simple calculations to determine ACH. By measuring the concentrations and decay rate of tracer gases, data loggers have the potential to measure ACH. Data loggers provide a significantly less intrusive, cheaper, and more reliable alternative to measuring ACH. This method allows for repeated measurements, which add to the precision of the determined ACH calculations. *Offer a less labor-intensive approach to analyzing a building’s envelope.