The Dwelling Vitality Audit and The Blower Door Check for Dwelling Airtightness
Today there is an unprecedented amount of financial incentives to build energy efficiently. These incentives come from state and federal governments, utilities, manufacturers, and others. Together they add up to thousands of dollars per home. Most of the money can only be accessed by doing a systems analysis. John Bushnell of Bushnell Energy Consulting says, “Typically, our service pays off by making sure you receive all of the energy efficient incentives currently available.”
Professional energy auditors like John Bushnell use blower door tests to determine a house’s airtightness. The Energy Saver 101 infographic explains the importance of a blower door test during a home energy audit. – energy.gov/articles/energy-saver-101-infographic-home-energy-audits
A home energy audit is often the first step in making your home more efficient. An audit can help you assess how much energy your home is using and what steps you can take to improve efficiency. But remember, audits alone do not save energy. A home energy audit shows where energy is being lost in your home and what you can do to save money.
Here are a few reasons for determining proper building tightness:
- Reduction of energy consumption through air leakage
- Avoiding problems with moisture condensation
- Avoid unpleasant drafts caused by cold air from outside
- Determine how much mechanical ventilation might be required to maintain acceptable indoor air quality.
A fan door test locates air leaks using a special fan to depressurize a house.
How they work
A blower door is a powerful fan that is built into the frame of an exterior door. The fan draws air out of the house and lowers the air pressure inside. The higher outside air pressure then flows through all unsealed cracks and openings. The auditors can use a smoke pen to detect air leaks. These tests determine the rate of air infiltration into a building.
Blower doors consist of a frame and flexible panel that fit into a doorway, a variable speed fan, a manometer to measure the pressure differences inside and outside the house, and an airflow manometer and hoses to measure the airflow.
There are two types of fan doors: calibrated and uncalibrated. It is important that auditors use a calibrated door. This type of blower door has several gauges that measure the amount of air that the fan is pulling out of the house. Uncalibrated fan doors can only locate leaks in homes. They do not provide a method for determining the overall tightness of a building. The calibrated blower door data enables the auditor to quantify the extent of air leakage and the effectiveness of each airtight job.
Preparation for a blower door test
Follow the steps below to prepare your home for a blower door test:
- If you are heating with wood, make sure that all fires are completely extinguished – not even coals – before the auditor arrives. Remove all ashes from open fireplaces.
- Schedule a tour of your home with the auditor. Be ready to point out areas that you know are drafty or difficult to comfortably condition.
- Expect the auditor to request access to all areas of your home including closets, fitted wardrobes, attics, crawl spaces, and unused spaces.
- The inspector must close all exterior doors and windows, open all interior doors and close all chimney flaps, doors and air inlets for wood stoves.
- Expect the auditor to check all atmospheric fossil fuel devices to make sure they are not triggered during the test. The auditor should return them to their original position after the test.
- Expect the test to take up to an hour or more depending on the complexity of your home.
While there are many financial incentives out there, they won’t last forever. Rust never sleeps and the ancillary costs never fall. In any case, it makes sense to test your house or your business building for airtightness and to check which investments you can save costs in the future. Here in the Greater Puget Sound Region, bushnellenergyconsulting.com conducts house energy audits. The goal of home energy audits is to save you money while providing a cozy place to live.
This blower door test information is provided by energy.gov/energysaver/blower-door-tests