What I'm Seeing Now


How To Tell The New Windows Weren't Insulated Properly When Installed

One of the most common things seen on older homes is the installation of new windows and this is how to tell the new windows weren't insulated properly when installed.

The Best Practice on new construction is to foam around windows and doors with a minimally-expansive, open-cell foam.

This provides a great energy seal impeding air flow, but also acts as very good insulation.  It controls sound better too!

The windows and doors are more firmly held in place as well.

In the olden days they stuffed regular fiberglass insulation around windows and doors.

It was more haphazard, and probably not entirely effective, but at least there was insulation.

Inspecting this house I noticed something around what were advertised as "new" windows -


Staining in the form of air that is exiting the house. 

If air is exiting the house air is also entering the house.

This is a process called infiltration and exfiltration.  It is not a good condition.  Air should not move so easily from out to in, and in to out.

This house has forced air heating and air conditioning.  This pressurizes the house and can force air out of any gap.  When the system turns off the air pressure equalizes again, drawing air back inside. 


What problems does such inefficiency around windows and doors lead to?

  • Discomfort during the different seasons - rooms that are too hot and too cold
  • The introduction of unwanted moisture
  • Super energy inefficiencies when the HVAC is operating
  • Pollutant and allergen movement into the house

These are not bad windows!  They are vinyl, double-pane, and the sun cannot be felt through them - all desirable.  What can we conclude about the installation of these new windows?

That they were slapped into place and likely have no insulation around them.  In fact, there are probably large cavities all around.


There are two things necessary for new window installation to be an IMPROVEMENT:

1.  That they are a good quality window and
2.  That they are installed professionally - they are level and plumb, secured properly with shims and the right nails or screws, taped outside to seal them against moisture intrusion, and are insulated well, preferably with foam. 

These two things are certainly a Best Practice.

My recommendation:  when windows and doors have been replaced, see if you can determine who installed them - a neighbor or relative, or a professional company with professional and trained employees.  If it's the former you may not have the "improvement" desired and the purchase is not what it is cracked up to be or hoped for.  And look for clues that the installation was a good one!



Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560


Comment balloon 14 commentsJay Markanich • April 26 2014 03:21AM


Too complicated for the average home owner.  We have to rely on the companies that do the installation.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) over 6 years ago

Just way to much data for me.  Sadly we all rely on the people installing the windows, doors etc to be upstanding in their ethics and work.  Most of the time it works other not so much

Posted by James Dray, Exceptional Agents, Outstanding Results (Fathom Realty) over 6 years ago

Good morning, Jay.... there are too many "handymen" doing jobs beyond their pay grade....

Posted by Barbara Todaro, Marketing Agent for The Todaro Team (RE/MAX Executive Realty ) over 6 years ago

Lenn - hopefully I have just taught a zillion people what to look for when the window installers are in their house!

James - actually most of the time it does not work.  A friend of mine is one of the original thermal imaging people in the country and he says 95% of windows are not installed properly.  It's simple really - put up, insulate with foam, trim.

I agree Barbara.  This is a national problem, to be sure.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

Thanks for the tip, Jay.  I'm getting some new windows later this year and will keep an eye on the install!

Posted by Gabe Sanders, Stuart Florida Real Estate (Real Estate of Florida specializing in Martin County Residential Homes, Condos and Land Sales) over 6 years ago

Keep a very close eye Gabe!  Now you know some of the tricks to look for.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

Yes, this seems to be a problem for many - the installation.  It's important to do your homework on the installers. - Debbie

Posted by Women of Westchester Working Together, Women helping Women get ahead (Women of Westchester Working Together) over 6 years ago

Good morning, Jay. But... But... But... It was inspected by the Codes Department! Surely, you must be wrong!

Posted by TeamCHI - Complete Home Inspections, Inc., Home Inspectons - Nashville, TN area - 615.661.029 (Complete Home Inspections, Inc.) over 6 years ago

Jay, I am also guessing this is a two story house?

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) over 6 years ago

Homeowners assume that professionals all do professional work Debbie.

That's doubtful Michael!  This install was within the last year, and the house is 30 years old.

'Tis Charlie.  In front is the glorious Z brick (those guys should be run out of town) and did not show this pattern clearly.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

 Sounds like a "special" that the sellers bought not knowing how special the contractor really was !

Posted by Sally K. & David L. Hanson, WI Real Estate Agents - Luxury - Divorce (EXP Realty 414-525-0563) over 6 years ago

They got the blue plate special with that one S&D! 

Or not so much.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

When you say new windows, do you mean replacement type or new construction? Often the replacement windows are not installed as you describe. To do so would require removal of the trim work, not typically done. 

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) over 6 years ago

Replacement Jim, with all new woodwork inside and out.  Looking at other houses nearby, the old windows required that, so the cavities were exposed.  They are good windows, though.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

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