Posts Tagged ‘blower door’

Ways to Save on Heating Costs

December 19, 2013

One of our newest locations, Buckeye Heating and Cooling, was featured on the news in Columbus Ohio.   Technician Jeff Walsh spent some time performing a home energy audit and using the infrared camera.  Nice work Buckeye Heating and Cooling!  I think central Ohio just got a little warmer!  Not in Ohio, find a location near you!

You can view the Buckeye energy audit video here.



Great Video of Home Performance in California

August 24, 2011

Here is a great video from  the California Center for Energy Sustainablity describing the Home Performance Process featuring  one of our GreenHomes America Partners: ASI Hastings.  Great work! Enjoy!

Infrared thermography, a remarkable tool!

December 15, 2010

[Although this appears under my byline, the following is a guest post from John Snell.   John is the founder and a partner in The Snell Group and works as an Instructor, Consultant and Director of Curriculum.   In 1994 John had the honor of becoming one of the first thermographers in the world to obtain a Level III Thermal/Infrared certificate from ASNT.  John knows IR!  And at GreenHomes, we agree the infrared thermography is an important diagnostic tool and a standard part of every audit.]

John Snell using an infrared camera

John Snell using an infrared camera

Many homeowners are having high-quality energy audits conducted by trained professionals. Honestly, it is the only way to ensure work will be done properly and yield effective results. More and more auditors are now using infrared thermography as part of that process. It only makes sense as thermography can both speed up an audit and make it much more effective. In the end, this extra bit of work makes lots of sense for everyone involved in making a home more energy efficient.

Infrared image showing thermal defects in a house

Infrared images can help locate and identify thermal defects in a home.

What should you know about infrared? First, it is not magic! We cannot see through walls and much of what we learn is based upon a greater understanding of the building. Typically we can find the framing and any existing insulation. This should make any bids for insulation work more accurate and lower in cost because they are based on reality. When used in conduction with a blower door, always recommended, we can also find sites of air leakage. Again, this will make the air sealing work much more cost-effective.

Second, the thermographer needs to not only be formally trained but also have the kind of qualifying experience that will make s/he the expert you want involved in your project. Thermography looks simple! It is not “rocket science” but it does require basic training and experience to become an expert.

The dark areas in this imagine show problems areas in several stud cavities that warrant further investigation

Imaging systems are electronic “cameras” that are sensitive to seeing heat that radiates from all surfaces. An insulated wall will look different than an uninsulated one as will the framing and any air leakage. The thermal image is usually quite easy to “read” especially with the help  of a knowledgeable auditor; the images, either in color or gray scales, can delivered to you electronically or in a printed form. Not all imagers on the market will yield good results in buildings so, if you have any doubt about the end results, ask the auditor if their system meets the minimum standards required by RESNET.

A “test out” infrared inspection may also be done after the work is in place to provide assurance the work has been done to high quality standards. Even with the best of crews this is an important piece of “insurance” for everyone involved. If you are the building owner, it may also be useful to you to obtain or purchase copies of the inspection report so that that information can follow the building through its life cycle.

I’ve looked at thousands of buildings since I first used this remarkable technology in 1983. While standards suggest an 18F inside to outside temperature difference is required to locate insulation issues, the truth is with modern imagers and a skilled thermographer, we can often work with less of a difference and we can now work nearly all year long. When the auditor schedules the inspection, they may pump up the heat, close windows, open up interior doors or turn down the AC (if you have it), all to get better imaging conditions. The auditor will also need full access to all of the inside and outside of your home. The whole inspection will only add about 30-60 minutes to the audit and, in the long run, you’ll see significant savings of time as a result.

An investment in a thermography inspection will yield quite a return! In fact, I cannot imaging auditing a building without an imager (and blower door). It just doesn’t make sense.

Thinking Thermally!

John Snell
The Snell Group

A “Gold Star” Audit

May 6, 2010

What does a “Gold Star” energy audit look like?  It looks just like the audits that GreenHomes provides.

Audit Image

The idea behind a Gold Star audit is an accurate and actionable.

To be accurate, the audit needs to include a good inspection and a range of diagnostics including combustion safety, infiltration (using a blower door), duct leakage testing, and an infrared scan.  If the person conducting the audit is making cost-effectiveness recommendations, then they need to have a firm understanding of local installation costs by a quality contractor—if they don’t know these exact prices they can’t talk about cost effectiveness!  And only by accurately determining how your home is operating, can we determine how much you can save.

To be actionable, any recommendations for improvement need to be easily understood by you and easily communicated to an installation contractor who can fully execute the recommendations.  For example, if the recommendations are for attic air-sealing and insulation (you shouldn’t do the insulation without the air-sealing), the person doing the work needs to understand exactly what needs to be done and be able to deliver (assuming the recommendations are accurate—see above!).  

A simple “clipboard audit” or home energy rating won’t cover both of these for you, so make sure you get what you need!  And don’t waste your money on what you don’t!

For a bit more background and additional links, see my earlier posts, our website, or the video description above.


Home Energy Audit Video

September 23, 2009

Audit Image

I’ve mentioned home energy audits here before.  We’ve just re-posted a short video that quickly walks through the process and touches on several of the keys elements of an audit.  Check it out!


Home Energy Audit Video

September 16, 2009

Audit ImageI’ve mentioned home energy audits here before.  We’ve just put together a short video that quickly walks through the process and touches on several of the keys elements of an audit.  Check it out!


Home Energy Audits

May 7, 2009

We’ve seen a big increase in interest in home energy “audits” over the last couple of months (of course, we approach every house this way—prescription and treatment without diagnosis is malpractice!).   As such, it’s probaA blower door is used to measure and locate air-leakage in a homebly worth pointing folks back to some previous posts.  Home assessments make a lot of sense—in fact they’re important—if they’re done right.  I thought I’d take the opportunity to revisit that topic and highlight some additional related information.


What is a Blower Door Anyway?

August 11, 2008


The short simple version:  A blower door is a diagnostic tool used to figure out how leaky a house is and where the leaks are.  It is a powerful fan that mounts into an exterior door and pulls air out of the house, simulating a strong wind on all sides of a house.  Anyone doing an audit of your house or sizing a furnace or air-conditioner should use one.  Unfortunately, most contractors don’t.  You should look for contractors that do.

The slightly longer version: The blower door measures the air tightness (or conversely, the leakiness) of a house and to help find where leaks are.  The blower door consists of three primary components.  First is the fan, calibrated to measure air flowing through it.  Second is a fabric or rigid shroud that fits in an opening of the house, generally an exterior door and seals the fan body into the envelope of the house.  And third, is a manometer, a device to measure the pressure created by the fans airflow.   The combination of the fan’s flow and the pressure difference it creates between the inside and the outside—giving us a standardized measure of air tightness.  

We typically measure leakage rates at a standard number of Pascals (a small unit of pressure).  Leakage is measured in cubic feet per minute (U.S.) and usually at 50 Pascals.  (The number is expressed as XXX CFM50.)

Often this number is converted to air-changes per hour, how many times the air in a house turns over each hour.  

What you need to know is that your contractor should use a blower door to measure air-tightness before and after any major project that impacts the energy use in your home.  Ask for it.

If you dying to know more, Home Energy Magazine has an excellent overview article in its archives.

I’ll talk about IR scans (infrared thermography) another time.


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