Professional energy auditors use blower door tests to help determine building performance and airtightness. There are a variety of reasons for establishing the proper building tightness. Reducing energy consumption due to air leakage is one of the primary considerations. If your parents were anything like mine, they wouldn't want you heating or cooling the neighborhood. That's exactly what you're doing with a leaky building. However, all structures should be allowed to breathe.Natural and mechanical ventilation are good for indoor air quality. If a building is too tight, it can been very harmful and in some cases even fatal. This is where a blower door test is truly useful. It measures the air leakage of your building and helps your Eco Evaluator pinpoint the exact problem areas. When a blower door is combined with a thermographic inspection, these tools provide a complete picture of areas to be addressed including moisture or condensation problems and uncomfortable drafts caused by cold air leaking in from outside.
How They Work
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure flows into the building through all unsealed cracks and openings. The auditor may use a smoke pencil or puffers to detect air leaks. These tests determine the air infiltration rate of a building.
Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and a manometer and hoses for measuring airflow.
There are two types of blower doors: calibrated and uncalibrated. It is important that auditors use a calibrated system. This type of blower door has several gauges that measure the amount of air pulled out of the house by the fan. Uncalibrated blower doors can only locate leaks in homes. They provide no method for determining the overall tightness of a building. The data from the calibrated unit allows the auditor to quantify the amount of air leakage and the effectiveness of any air-sealing job.
Preparing for a Blower Door Test
Take the following steps to prepare your residence or commercial building for a blower door test:
- Close windows and open interior doors
- Turn down the thermostats on heaters and water heaters
- Cover ashes in wood stoves and fireplaces with damp newspapers
- Shut fireplace dampers, fireplace doors and wood stove air intakes
- Restrict pets to a safe and secure location
Source: www.DOE.gov
