Significant improvements in Energy Efficiency became possible when Pressure Testing on Building Envelopes and HVAC Duct Systems became standardized and repeatable using the same test conditions. ANSI/RESNET/ICC 380 Standard was developed to establish testing of Building Enclosures and Air Distribution systems. This made the process of testing buildings and quantifying air leakage used in the Energy Code and Energy Efficiency software.
Green Building Energy Sustainability (GBES) has Energy and Mechanical Engineers, certified RESNET HERS Raters, and ICC certified Energy Inspectors to perform our inspections and pressure test. GBES also has Level 1 and Level II Thermographers to use Infrared Scans as necessary for our inspections and evaluations.
Residential and Commercial buildings have different pressures and requirements, but the general process is the same. You depressurize the building using a Blower Door by a specific pressure difference (measured in Pascal – Pa) to get the airflow out of the building. That will determine how much is leaking into the building, and using an Infrared Camera, and you can see where the air is leaking into the building and seal it. If you equate that airflow to volume in the structure, then you have Air Changes per Hour (ACH) used on Residential buildings. If you equate that number to the surface on the interior of the building, then you have Cubic Feet per Minute (CFM) per Square Foot for Commercial buildings.
HVAC system duct leakage is tested with a Duct Fan. It also measures airflow in CFM when connected to the HVAC system. If that CFM number is equated to the number of Square Feet in the building floor, you get the % of duct leakage per square foot of the floor area. Energy Efficiency and indoor comfort are dependent on the condition air being treated and effectively delivered to each room. If outside air leaks into the return system (think of an HVAC system located in the attic), then you are conditioning air that is a different temperature than the interior of the building. If air leaks out of the supply ducting, there will not be enough airflow in one or more rooms to heat or cool it properly. The 2021 IECC limits duct leakage to 4% of the flooring square footage.
The Manual D calculations of the HVAC system will provide a specific CFM requirement for each room that is then measured with a Duct Flow Hood. Testing each register will tell you if the duct system meets its delivery specifications.
GBES can pressure test your structure or duct system to see if it meets design specifications or Energy Code requirements. Please give our staff of Engineers a call to help you with your project. Our Office number is 940-808-1430.We have a dedicated phone for our Spanish-speaking clients. If we can answer questions or schedule an inspection, please call us at 682-246-8150