Thermal Camera Loan Program

Starting on Earth Day - April 22nd - 2017, Fairfax County residents can reserve thermal imaging cameras from any branch of the Fairfax County Public Library.  Reserve a camera just like a book through the library catalog, and it will be shipped to your local library branch for pick up.  To see the camera in action, watch our video.

Fairfax County is making these cameras available so that residents can inspect their home or business for hot and cold spots, which often indicate energy saving opportunities.  By implementing some of the weatherization improvements identified below, residents can make their home a more comfortable place to live while reducing utility bills. ENERGY STAR® estimates that air sealing and insulation improvements can save an average of 17% on heating and cooling costs for homes in our area.

Operating the Thermal Camera

Thermal imaging cameras use color to show the relative temperature of objects: cold is purple, moderate is red, and hot is yellow.  In the winter, purple spots inside your home indicate a lack of air sealing or insulation.  In the summer, these spots would appear yellow instead.  The camera takes thermal and regular pictures simultaneously, so you can always check what your photo really looks like.  In this image both walls look the same to the naked eye, but the thermal camera reveals that the exterior wall on the left is colder.  NOTE: This webpage uses winter images, when the goal is to eliminate purple areas inside a home.

Although the library catalog lists three camera models, there are actually four in circulation.  The iPhone camera compatibilities are virtually interchangeable and most are Generation 3.  If you need the Generation 2 iPhone camera to attach to a 5 or 5s, contact

Energy Saving Opportunities

To best identify energy saving opportunities, there should be at least a 20-degree temperature differential between the inside and outside of your home.  If possible, use the camera in the morning before your home has had the chance to heat up from the sun. 

Common culprits for air leaks include doors, windows, exterior outlets, ducts, and connections to the outside such as cables or plumbing fixtures.  Areas that might need additional insulation include attics, walls, floors, foundations, crawl spaces, and ducts.  Older homes that have not been well maintained can usually benefit the most from air sealing and adding insulation.  Air leaks and insulation gaps are also often created during renovations, when contractors are drilling holes or moving insulation around. 

Examples of short, medium, and long term projects are provided below, but every home and every homeowner is different.  Whether you prefer to hire a contractor or do the work yourself is up to you.  More information for do-it-yourselfers can be found on the ENERGY STAR website.  If you aren’t sure what your results mean, consider hiring a professional to conduct a home energy audit.

Short-Term Projects

Short-term projects use inexpensive equipment that can be found at your local hardware store.  Many homeowners will feel comfortable performing these upgrades themselves.

Drafty Door: Drafts often occur under exterior doors.  Add door sweeps to both regular and screen doors and check that existing door sweeps are in good condition.

Leaky Windows: Even new windows can let air pass through around the edges.  Add extra weather stripping along drafty spots, such as the underside of windows that open and close. If a window is drafty along the outside of the frame rather than along the window itself, caulk is needed rather than weatherstripping.

Leaky Outlets: Exterior wall electrical outlets are often uninsulated.  Block airflow by inserting socket sealers underneath outlet plate covers.  For safety, you should always de-energize the circuits serving any outlets you will be working on.

Electronics on Standby: Electronics can still use electricity when not being used.  Install a smart power strip to stop electricity from flowing to unused devices.


Medium-Term Projects

Medium-term projects use equipment that typically must be ordered online.  Many homeowners will feel comfortable performing these upgrades themselves.

Drafty Fireplace: Fireplaces and wood burning stoves are classic areas for heat loss since chimneys need to exhaust smoke while fires are burning.  During the summer months when your fireplace is not in use you can temporarily block air flow with a chimney balloon or fireplace plug.

Uninsulated Attic Door: Even well-insulated attics can be missing one key component – an insulated attic door.  A variety of attic door covers are available depending on the size and type of your door.

Long-Term Projects

Long-term projects are often performed by a contractor that specializes in energy auditing or insulation.  Many homeowners will not feel comfortable performing this type of renovation themselves.

Inadequate Insulation: In the picture on the left below, missing pockets of insulation are revealed by dark purple spots.  If insulation needed to be added everywhere – i.e. the R-value was simply too low – the ceiling would appear more uniformly pink or purple. 

Insulation often gets moved when installing ceiling fixtures such as recessed lighting.  Whenever you place insulation near a hot object such as a light, remember to take safety precautions such as using an attic insulation shield to avoid starting a fire.

Uninsulated Foundation: Home foundations are often uninsulated.  It is also common to find air leaks between the foundation and the bottom of the house.

Uninsulated Crawlspace: Many homes have crawl spaces under one area of the house where an addition has been added.  In the picture on the left below, the yellow portion is located above a finished basement while the purple area is located above a poorly insulated crawlspace.

Leaky Duct: The ducts that provide conditioned air throughout your house can also be uninsulated and leaky.  The yellow in the picture on the right below reveals where a duct is located under the floor.  If your ductwork is exposed, you can insulate and seal it yourself, but ducts located under the floor will likely need to be worked on by a professional HVAC technician.

Contact us at  We want to hear from you!  Where did you find leaky areas in your home?  What are some other helpful project ideas?  Send us your before and after photos to be added to our website!



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