Chris' Corner: Energy loss through ductwork leakage and how to prevent it!

Energy loss through ductwork leakage and how to prevent it!


Jay Markanich, a property inspector from Bristow VA wrote this post on heat loss within a home through gaps in ducting.  Almost all homes with ducting will have this issue to varying degrees.  He also offers a very pragmatic solution.  If you are interested, read on:


At least that's what I heard over the phone.  I thought this might be a job for Mighty Mo.

I named my thermal camera "Mighty Mo."

Being a life-long Washington DC guy, as a child we used to go out to the Hot Shoppe's Drive In.  That was the Marriott family's first business venture in town.

It was a drive up restaurant, where you would order from a menu with a microphone, and get served by girls on roller skates, and eat in the car.

Their two signature offerings were A&W Root Beer (standing for Alice and Willard) and the Mighty Mo hamburger.

These long preceded the McDonald's Big Mac or Burger King's Whopper.

The Mighty Mo's were real popular and a highlight of my childhood!

But I digress.

Breaking out the IR camera "Mighty Mo" I had a look around.  Wow! 

Let me demonstrate energy waste, heat and cool.

The image on the right shows where an HVAC duct goes through the sub floor to service the dining room above.  It is visible from the unfinished basement.  The hottest area looks white, and it is hot - 124F!

Where is a lot of the energy going?  Down and into the basement!  Woohoo!  But why?

The register flange has serious gaps between it and the subfloor and it and the hardwood flooring above.  This is the narrowest gap I found.  One was 1/4" wide.

Every register on the main level looked like this.

Looking into the registers on the upper level, carpeted, similar gaps were visible.  With similar energy leakage. 

Multiply this by all of the registers in the house (11 main level, 8 upper level) and that is a lot of energy going where you don't want it!

It is a huge wast of an efficient system.


This is an older house, 1979.  I knew when they called that the duct work was likely all metal.

These are famous for energy leaks!

See the service tubing on the image above right?  It is round and metal.  That likely is used throughout the house.

Now look at the lower image to the right.  The whitest rectangle is where the register enters the room above.  Look at all the energy leaking around it!  Where is it going?  Between the floor above and drywall below.  HEATING AND AIR CONDITIONING A DEAD SPACE!  I also suspect that the tubing has come apart, but couldn't see because the register comes up UNDER the bureau!  So not only is it leaking air, it is blowing what's left UNDER the bureau! 

"There is no where else to put the bureau," I heard.  Well, that might also have something to do with the efficiency!

My recommendation:  pop the registers off each of your HVAC ducts and check for gaps.  If you see any, give them a good caulking.  I recommend a good siliconized acrylic or Elastomeric caulk which has the ability to stay supple and expand and contract with temperature changes.  It might be a cheap way to improve your energy efficiency, even if it's only 10 or 15%!  And done once and you're done! 

And call a guy with a thermal camera.  There aren't many of us for a reason.  We're all really cute.




Jay Markanich Real Estate Inspections, LLC

Based in Bristow, serving all of Northern Virginia

Chris Smith CSSBB
          Sales Representative

Interested in Buying or Selling Real Estate?

  ph: 1.866.936.3500

Chay Realty Inc.,

Comment balloon 0 commentsChris Smith • April 02 2011 09:01AM