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ENERGY SAVINGS in buildings
AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
APPLIANCE EFFICIENCY RATINGS
BASEMENT HEAT LOSS
BLOWER DOORS & AIR INFILTRATION
CATHEDRAL CEILING INSULATION
COMBUSTION AIR for TIGHT buildings
DEW POINT CALCULATION for WALLS
DEFINITION of HEATING & COOLING TERMS
DUCT SYSTEM & DUCT DEFECTS
ENERGY STAR PROGRAM
FLOOR RADIANT HEAT Mistakes to Avoid
FRAMING DETAILS for BETTER INSULATION
FREEZE-PROOF A BUILDING
GREEN BUILDING CONSTRUCTION
HEAT LOSS in BUILDINGS
HEATING COST SAVINGS METHODS
HOUSE DOCTOR, how-to be
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION INSPECTION & IMPROVEMENT
LEED GREEN BUILDING CERTIFICATION
SOLAR ENERGY SYSTEMS
THERMAL IMAGING, THERMOGRAPHY
THERMAL MASS in BUILDINGS
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
WINDOWS & DOORS
WINTERIZE A BUILDING
How to find & fix building air leaks to stop unwanted heat loss or heat gain:
This article discusses air sealing strategies for building retrofit to save energy costs and stop air leaks & forms the home page for our series of articles on how to find and stop both air leaks & un-wanted heat loss or heat gain in buildings. The sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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The question-and-answer article about strategies for sealing air infiltration leaks on buildings (or air exfiltration leaks, i.e. heat loss), is provided in full-text below, and discusses steps to take to be sure that the energy retrofit cure is not worse than the disease, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
Air Sealing the Building Shell to Save on Energy
In most cases, the most cost-effective energy-savings retrofit - after installing a low-flow showerhead (very inexpensive) - is to air-seal the building shell. If you are planning to add insulation to uninsulated wall and ceiling cavities, then air sealing is essential to reduce the risks of moisture damage and to be sure that air leaks do not overwhelm the benefit of the new building insulation.
Our photo (left, D Friedman) demonstrates a common point of air leakage around windows on a New York home constructed in the 1960's. Taking advantage of a project to install new interior window trim, we found, insulated, and sealed these 1/4" to 1/2" air gaps around the building's windows and doors.
Details are at AIR LEAK SEALING PROCEDURE.
To ensure success with energy retrofits to reduce heating or cooling costs for a building, you have to consider the whole building as a system and you need to coordinate different aspects of your work. Otherwise you may not get the energy savings and other benefits that you expect. In the worst cases, you can worsen existing heating or cooling cost problems, or create new ones.
For example, if you add insulation to a house with a wet basement [see WATER ENTRY in BUILDINGS] and fail to seal off airflow paths from the basement to the attic, you are likely to find a frosted attic ceiling, and even wet ceiling or attic insulation, or worse, a costly mold contamination problem.
At the outset, then, you should assess the problem and plan a strategy. This will vary depending on the building type, site conditions, and the idiosyncrasies of the particular building. You will need to determine the major paths of air leakage and the major paths of moisture transport in the building. At the same time, you need to identify any problems that air sealing might cause or exacerbate. Based on this analysis you can plan a reasonable course of action.
Find the Air Leaks in the Building
There are two main types of air leaks in buildings - direct leaks through the exterior walls or ceiling to the outdoors, and indirect air leaks through interior partition walls, ceilings, or stairwells and plumbing chases. Sometimes there are surprising air leaks into a building's air duct system as well. In many cases the indirect air leak paths account for more leakage (and energy loss) than is evident, particularly in older, balloon-framed homes.
A trained eye can pick out many of the obvious air leaks - around heating baseboards, door casings, doors and windows, attic access hatch or stairway, and at electrical receptacles. Less obvious are air leaks around bathtubs, built-in cabinets, kitchen soffits, medicine cabinets, and interior stairwells. Depending on their location, these may leak either directly or indirectly to the outdoors.
Where possible, indirect leaks are best dealt with at the source, which may be accessible in the basement, crawl space, or attic. Plumbing and chimney chases, open-topped partition walls, and stairwells are often the main culprits. These should be sealed off in both the basement and attic where possible.
Other building air leaks are not so obvious and require a thorough understanding of the structure of the building. Many of these leaks are unaffected by the presence of a polyethylene air/vapor barrier unless the barrier itself was meticulously sealed at corners, intersecting walls, and wire and plumbing penetrations. Otherwise, breaks in the poly line up nicely with breaks in other building components to encourage aggressive air flow where you might not expect nor want it.
Listen to the building occupants' observations regarding drafts and cold spots. They can clue you in to which retrofit measures will most affect their comfort, though these are not necessarily the ones that will most affect heating or cooling costs for the building.
To track down the more tricky air and heat leaks and to evaluate the real effect of your efforts, expensive monitoring equipment - fan door (blower door) and infrared scanners (thermography) are available. In lieu of a blower door test, an attic fan can be used to pinpoint leaks with a smoke gun, a cigarette, or even talcum powder. Even with top equipment, though, judgment and experience are needed for success in stopping air leaks and reducing building energy costs.
See BLOWER DOORS & AIR INFILTRATION and
see HEAT LOSS DETECTION TOOLS for more sophisticated and accurate methods of detecting points of un-wanted building heat loss or heat gain.
At THERMAL TRACKING & HEAT LOSSwe describe other visual clues that can help spot points of significant air (and heat) leakage in buildings.
At ENERGY SAVINGS RETROFIT CASE STUDY we include the air sealing results for an older, costly-to-heat home for which simply adding insulation didn't do the trick.
How to Solve Building Moisture Problems
At the same time, the contractor should be keeping a lookout for evidence of existing or potential building moisture problems. Telltale signals are peeling paint on the building exterior
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