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Help and Ideas For Your Home Remodeling Project

Home Project FYI.  - Help and Ideas For Your Home Remodeling Project

Finding Air Leaks in Your Home

Air Leaks: How an Infrared Camera Can Help You Find Themair leaks

Infrared (IR) cameras are quickly becoming an indispensable tool for home inspectors.  Reading the thermal images produced by an infrared camera during an inspection allows for quick and accurate identification of defects and air leaks that may not always be immediately apparent to the naked eye.

Infrared camera imaging is especially useful when looking for air leaks, including insulation defects, during an energy audit because it allows the inspector to actually view the apparent temperatures in a given area.

By purposely controlling the temperature and air pressure in the interior of a house, air can be forced inside through cracks and holes.  Using an infrared camera, the sources of these air leaks can be quickly located and visually documented.  Areas of insufficient insulation also become more apparent when viewed through an infrared camera and can be visually documented, as well.

How Infrared Cameras Work In Finding Air Leaks in Your Home

While there are other infrared tools available, such as spot radiometer and thermal line scanners, a thermal imaging camera is the most accurate device to use for energy-audit inspections and to help locate air leaks.  The infrared camera reads infrared radiation in order to express heat differences and temperature signatures.

The infrared camera sees light that is within the heat spectrum that exists just beyond the spectrum that can be seen with the naked eye.  Differing heat signatures are displayed in the camera’s viewfinder as a gradient color scheme, with hotter areas displayed as brighter colors, and cooler areas as darker colors.


An inspector can view this information on the infrared camera in order to make observations and find defects and air leaks.  By viewing the hottest and coldest areas, inspectors can collect valuable data about the building envelope.  Images taken with the infrared camera can be included alongside digital photos of the same problem area in the inspection report.

Before Looking For Air Leaks

Equipment should always be checked before the inspection.  Make sure batteries are charged on the infrared camera (as well as the laptop, digital camera, and any other equipment that will be used).  Find places to charge equipment on site, if possible, in order to avoid any delays associated with dead batteries.  If the inspection is likely to take a while, such as for a very large property, it may be a good idea to have extra batteries charging while performing the first part of the inspection.  This way, batteries can be switched out if they die while gathering data.

Any digital storage media should also be checked for adequate memory so as not to run out of room while saving images, which are important as the visual documentation of the problem areas.  Digital images of problem areas should be saved next to thermal images for comparison, so it is important to have plenty of memory in cameras and on data cards for both types of cameras.

Setting Up for an IR Thermal Imaging Inspection

Because the infrared camera shows differences in heat signatures for a given area, it is important to set up the testing conditions such that the temperature difference between the interior of the house and the air outside is as large as possible.  The peaks of the heating and cooling seasons for any region are generally optimal times to gather thermal imaging data, since heat or air conditioning can be run in order to maximize the temperature difference.

All windows and exterior doors should be closed during testing.  It is also helpful to move furniture away from walls so that they don’t block baseboards, and to remove curtains and blinds (or secure them out-of-the-way) so that accurate readings can be taken at areas typical for leaking air, such as at floor-wall joints and window frames.

Achieving a 15°  to 20º difference in temperature is ideal.  The heat or air conditioning should then be turned off, and the inspector should wait at least 15 minutes before commencing with the IR inspection.

Air Leaks From Insulation Defects

Once a solid difference in temperature has been established between the interior and exterior of the house, insulation defects can be viewed by the camera.  By looking at the difference in apparent temperatures, hot and cold spots can be identified as areas that may have missing or inadequate insulation.  If a potential problem area is pinpointed using the infrared camera, the insulation in that spot should be examined to verify that it is an issue and to gather more details on the exact nature of the insulation problem.  Was insulation moved during a fixture installation and not properly replaced?  Is the thickness of the insulation inadequate for the application?  These are the types of details inspectors can gather after locating an issue with the insulation.

Finding Air Leaks

Finding the sources of air leaks using thermal imaging requires some additional setup beyond what is needed to find insulation problems.  By changing the air pressure of the interior in relation to the exterior, air flow can be increased to force air through cracks and holes.  With the warmer or cooler air from the outside flowing into the house through the cracks and holes, inspectors can use thermal imaging to locate the sources of these air leaks.

The best way to pull air inside through cracks and holes is by using blower door equipment.  The blower door test creates ideal conditions for pulling air in through leaky spots, and these spots are then visible in the thermal image.  If blower door equipment is not available, a house’s exhaust fans and ventilation system can be used to create similar (though less controlled) conditions, allowing useful data to be gathered in the hunt for air leaks.

Areas to Check For Air Leaks

Knowing what areas to examine for air leaks and insulation issues will speed up the process of finding problems.  Infrared equipment is extremely useful for pinpointing the locations of air leaks and specific spots where insulation is inadequate, but it is also useful to know where to start looking for such defects.  Air leaks can often be felt with the hand during a blower door test.  Also, during cold months, areas of insufficient insulation may be apparent due to the change in temperature in specific spots.

Inspectors can start with the following areas, or any area that is already suspected of air leaks or lacking inadequate insulation:

  • air leaks at light fixtures;
  • electrical receptacles;
  • windows and doors;
  • attic access;
  • attic insulation;
  • basement rim joists;
  • cellar door air leaks;
  • crawlspace air leaks;
  • ductwork;
  • plumbing penetrations, and traps under tubs and showers;
  • air leaks around plumbing vent pipe penetrations;
  • chimney flue and fireplace surround air leaks;
  • dropped soffits;
  • dropped ceilings;
  • air leaks in kitchen soffits;
  • air handlers;
  • air leaks at cracks between partition top plates and drywall;
  • utility chases; and
  • baseboards.

By using thermal imaging, inspectors can more quickly identify problems with insulation and the sources of air leaks.


Understanding Insulation R-Value

R-Value of insulation can be a a little hard for some to understand.  This article can help you learn more about the insulation in your home.

As energy efficiency and energy conservation has become an increasing concern among builders and homeowners, the attributes and performance of building materials and components are being scrutinized more closely.  In order to maximize levels of efficiency by examining the details of how each individual component of a house performs on its own and as part of a dynamic system, very specific properties are measured and taken into account.  This can be especially helpful when trying to select the best building materials for a given application.  R-value is the measurement used when quantifying a specific material’s level of thermal resistance, which is the inverse of U-value, which measures thermal conductance.  R-value is often the standard consideration when discussing the effectiveness of insulation.  Homeowners who may want to add attic insulation or re-insulate their home may want to be familiar with the specifics of R-value ratings.

How Does R-Value Relate to Insulation?

Heating and cooling costs account for 50% to 70% of energy used in an average U.S. home. Inadequate insulation can account for a lot of heat loss and wasted energy, so it is important to be sure that the insulation installed is doing its job properly.
The right R-Value of this wall insulation is important The function of insulation is to provide resistance to the flow of heat, and R-value is the measure of exactly this attribute for a given material.  A higher R-value equates to higher resistance to heat flow and greater effectiveness in insulating and increased energy efficiency.  An insulation material’s R-value, in conjunction with how and where it is installed, will determine its overall thermal resistance and effectiveness.  Adding the R-values of each layer of material contained in one building component, such as a wall or ceiling with multiple layers of insulation, will help determine the thermal resistance of the whole component.  The way the insulation is installed, as well as other factors, will also affect its thermal resistance and energy efficiency. Attic insulation is one of the most common incorrectly installed insulated areas.

Important Factors to Consider When Measuring R-Value Thermal Resistance

When considering R-value as a means to determine the thermal resistance of a building component, there are other factors that must also be taken into account.  While R-values are an excellent guide for comparing the attributes of different insulation products, they apply only when the insulation is properly installed.  For example, as with attic insulation, if two layers of insulation are smashed into the thickness intended for one layer, the R-value does not double.  Likewise, if a single layer of insulation is compressed during installation, it will not be as effective.  Stuffing batt insulation sized for 5 inches into a 4-inch wall cavity will actually lower its R-value.  Good energy conservation is met by ensuring that attic insulation and all insulation is correctly installed. This will help allow the product’s full benefits to be realized while increasing energy efficiency and improving energy conservation.

Also important to consider is the fact that even when installed correctly, insulation affects heat transfer through the insulation itself but not through other materials, such as glass windows and studs.  If there are structural gaps in any building penetrations, even insulation with a high R-value that’s installed properly cannot mitigate heat loss from air leaks.  Studs and windows provide a parallel heat conduction path, and insulation between studs in a wall does not restrict heat flow through the studs.  This heat flow is called thermal bridging, and the overall R-value of the wall will be different from the R-value of the insulation itself.

Calculating and Converting R-Value

The equation used to calculate R-value may be of interest to some inspectors because if the R-value is known, the equation can also be used to help calculate heat loss.  The equation for determining R-value is as follows:

R-value = temperature difference x area x time ÷ heat loss

The temperature difference is expressed in degrees Fahrenheit, the area in square feet, the time in hours, and heat loss in BTUs.  Since European R-value uses different units of measure (Celsius, Kelvin, meters, etc.), it may be helpful to know how to convert a European R-value into a U.S. R-value.  This is done by multiplying the European value by 0.176 and dividing 1 by the result.

The FTC and DOE on R-Value

In the 1970s, the Federal Trade Commission (FTC) created a rule requiring insulation manufacturers to disclose R-values at the point of sale and in some ads.  This is intended to protect purchasers from false claims made by manufacturers and to create a standard of comparison for products.


The U.S. Department of Energy (DOE) has issued recommendations for insulation R-values in new and existing homes.  The recommendations are based on a comparison of the cost for installing insulation and increased energy efficiency versus potential future energy savings and increased energy conservation.  Their recommendations for attic insulation, cathedral ceilings, walls and floors are generally greater than what is actually required by most current building codes.

For good energy conservation, R-value ratings are a useful tool, especially when comparing the effectiveness of insulation products. Understanding a bit about how other factors affect a building component’s thermal resistance is important if insulation is to be used to its full benefit.

Homeowners who know more about insulation R-value will be in a better position to utilize this rating most effectively when it come to their home’s insulation and overall energy efficiency.

Here are some very useful and informative videos for insulation installation and use.

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