Skip to Main Content

Weatherization Assistance Program Technical Tools

Since the inception of the Weatherization Assistance Program in the mid-1970’s, the program has constantly evolved to today’s sophisticated whole-house approach – using advanced diagnostic equipment and state-of-the-art installation techniques to ensure the most cost effective use of program funds on every home. Early measures, such as storm doors, storm windows, and extensive exterior caulking have disappeared and been replaced by techniques such as blower door guided air-sealing, zone pressure diagnostics, dense-packing walls, advanced mobile home insulation techniques, and numerous other advanced practices. As the Weatherization network became better at air sealing and insulating houses, program technicians also learned more about the dynamics of building systems and the occupants’ interaction with those systems, helping pave the way for health and safety measures to be incorporated into the program. Weatherization professionals understand that the house is not a loose collection of unrelated systems, and analyze a house using a “whole house” approach that helps insure that weatherization will not just save energy and increase comfort, but have no adverse effects on the other components of the home’s performance – the humidity levels, indoor air quality, durability, structural integrity, and the occupants’ health and safety.

Diagnostic Equipment


Blower Doors

The blower door serves two main purposes:
  1. Measure the air leakage of the building;
  2. Exaggerate the air leakage for easier detection.

Blower doors are perhaps the most essential diagnostic tool for a weatherization professional, typically used by auditors, crews performing the work, and quality control inspectors. Auditors use a blower door to determine the amount of air flow in the house, determine the potential for savings by air sealing, identify major air leaks, and any possible problems that the weatherization crew may encounter related to air infiltration ad air sealing. The crew will use a blower door to help identify particular air leaks, patterns of air flow, detect duct leaks, conduct pressure diagnostic tests, and measure their progress on air sealing while helping insure they do not compromise indoor air quality by tightening a home too much. The Quality Control Inspector will use a blower door to assess that appropriate air sealing was done on the home, and that all significant and problematic air leaks were addressed.

Digital Combustion Analyzers

Digital combustion analyzers enable the heating system technician to perform health and safety tests, including testing for carbon monoxide, and to tune the furnace to its highest possible steady state efficiency. The combustion analyzer measures carbon monoxide, oxygen levels of the combustion gases, stack temperature, and steady state efficiency.

Duct Leakage Diagnostic Tools

Not only are duct leaks an obvious waste of energy, but they can also cause hazards to occupant health by causing poor indoor air quality or backdrafting of combustion appliances. Typically weatherization professionals test for duct leaks using either a duct blaster or a pressure pan in conjunction with a blower door.

Infrared cameras are being used more and more in the WAP to detect thermal defects and air leakage in buildings. A trained thermographer will use the IR camera to will detect patterns of heat or temperature changes in various objects such as walls, roofs, HVAC ducts, and other objects. An IR scan can identify thermal irregularities that indicate missing insulation and insulation defects due to damage, moisture and improper installation. The IR survey can also provide indication of potential areas of imminent condensation, moist or wet areas as well as air infiltration and exfiltration, especially when used in conjunction with blower door testing.