Air Leakage & Air Sealing
(Air leakage represents up to 40% of the heating costs wasted in residential structures!)
What can I do to better air seal my home?
+ Seal and insulate attic hatches! This represents a huge area of thermal inefficiency and air leakage in most homes. Simply installing good weather stripping to seal the attic hatch and insulating the hatch are two simple improvements that can lead to substantial energy savings.
+ Seal any openings noted in the exterior of the home.
+ Caulk windows, doors, utility, and all exterior penetrations around the home.
+ Seal plumbing and electrical wiring penetrations within the attic. Also, seal interior wall partitions and joints in building sections, if accessible. Caulking and foam are typically used to seal such areas.
+ Properly seal chimney penetrations through the attic with non combustible materials.
+ Duct air leakage typically wastes 10%-30% of heating energy purchased by homeowners. A duct blaster test can determine if air sealing ducts is warranted. Sealing ducts and insulating ducts in unconditioned spaces yields the biggest savings.
+ Weather strip exterior doors and windows.
+ Seal air leaks from the inside, whenever possible. Seal around heating supply registers, outlets, switches, etc.
+ Get a BPI Energy Audit! Energy audits are comprehensive audits of the home and include blower door and duct blaster testing together with infrared thermography and a comprehensive home analysis. Combustion appliances are also tested to determine efficiency, carbon monoxide levels, satisfactory draft, and if there is sufficient combustion air present. A BPI Energy Audit for most homes costs $450.
How much does my home actually leak?
Testing for air leakage is conducted with a blower door test. In essence, a blower door test consists of a big fan- installed in an exterior door- that depressurizes the home to a specific pressure (50 Pascals) and measures how much air is flowing through the fan in cubic feet per minute (CFM). Blower door tests will be required for all new construction in Washington State starting in 2011. Some states require blower door testing for all real estate transactions. Sealing air leakages in buildings represents a tremendous opportunity for energy conservation.
How much room for improvement is there?
Comparing the measured blower door air flow to the calculated minimum air flow for the home will tell us how much room there is for improvement. For instance, if the blower door measurement is 4000 CFM and the minimum air flow requirement for the home is 1500 CFM, an air sealing opportunity of 2500 CFM is possible before mechanical ventilation is required.
Can I make my home too air tight?
Yes! If the home is air sealed and subsequently measures below the minimum ventilation requirement calculated for the home, then mechanical ventilation would be required. This is not the end of the world, however. Mechanical ventilation is controlled ventilation, can be filtered, and can be coupled with a heat recovery ventilator (which takes heat out of the exhausted air and keeps it in the home). Uncontrolled ventilation brings in air from the crawl space, attic, and outdoors. It is important to conduct a blower door test after a home is air sealed to ensure minimum ventilation requirements are maintained for the safety of the occupants and the home.
Can you tell EXACTLY where my home is leaking?
Yes! Coupling a blower door test with infrared thermography, we are able to tell precisely where a home is leaking and specifically which areas should be targeted for air sealing. Infrared thermography will also specifically tell us what areas of the home would benefit from improved insulation.
This blog entry is not intended to endorse any person, product, or company but is intended to help educate viewers on the home buying and selling processes. The information provided is believed to be reliable but is not guaranteed by Coldwell Banker Island Living, nor do they add any implied warranties.
