DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > Windows and Doors > Measuring efficiency of builder grade windows?

Thread Tools Search this Thread Display Modes
Old 02-06-2012, 04:54 AM  
Join Date: Jan 2011
Location: Centreville, VA
Posts: 34
Likes Given: 3

Default Measuring efficiency of builder grade windows?

Hey Guys,
Our townhouse has many (18) windows, it was built in 1993. The windows are original builder-grade double-glazed metal windows.

I measured the temperatures of the windows and surrounding walls with an infrared thermometer. The windows are definitely a source of cold air in the house, the glass and metal are 10-15 degrees colder than the surrounding sheetrock.

Before I go out and spend $$$$$$ on new windows, I want to make sure new windows will really help keep my house warmer.

My question: Is there any way to measure the U-factor or other properties of my existing windows so I can compare them to what the salesmen quote for new windows?


drew2000 is offline  
Reply With Quote
Old 02-09-2012, 06:21 PM  
Junior Member
Join Date: Feb 2012
Location: Nashville
Posts: 2

I may be wrong, but the NFRC (The National Fenestration Rating Council) has a website that does ratings for stuff like this. Don't remember the URL, but I seem to remember them actually rating windows by manufacturer.

Not sure if there is a good way to directly measure.

Aaron5454 is offline  
Reply With Quote
Old 02-10-2012, 11:55 AM  
mudmixer's Avatar
Join Date: Sep 2006
Location: St. Paul/Minneapolis, MN
Posts: 658
Liked 73 Times on 56 Posts
Likes Given: 57


A windows will ALWAYS be colder than the walls in cold season. That is because a window is just a hole in the wall with some glass and gas in it. No matter what kind of gas and panes are used, the U-value will never be equal to any minimal wall. Just look at the listed U-value and compare it to the U-value of and uninsulated 8" concrete block and it will be about the same.

Also, they never tell you about the radiant heat loss that is very high at night in cold climates. Just a sheet hanging up at night does more good than any "gas" because the heat is radiated way through the glass from the source to the colder and darker area.

The metal frames also contribute to the heat loss because of conduction through the exposed aluminum, but a gap or vinyl barrier will give some minimal insulation.

I have a very good, tight and properly installed oversize sliding door. There is a world of difference at night just from dropping the 1" mini blinds down and tilting them, and it is instantaneous.

Just face it - If you want to see outside, you will lose some heat and there are limits on what you can expect from a window and a good installation can make a bigger difference than the salesman's numbers on insulation or U-value.

mudmixer is offline  
Reply With Quote
Old 02-12-2012, 03:47 PM  
Join Date: Jan 2011
Location: Centreville, VA
Posts: 34
Likes Given: 3


Thanks for the replies guys. I am definitely wary of the window salesman. That's why I was hoping to figure out how my current windows rate compared to new ones.

I don't trust any window salesmen period. I don't want to sink $10,000+ into new windows and still have the same problems.

drew2000 is offline  
Reply With Quote
Old 02-12-2012, 04:45 PM  
Contractor retired
nealtw's Avatar
Join Date: Nov 2010
Location: Upper Fraser Valley, British Columbia
Posts: 21,555
Liked 2453 Times on 2160 Posts
Likes Given: 4140


When we work around windows that are twenty years old, fixing rotten wood and the like we encourage people to change that window because we are there already and the labour is no difference. Nobody comes back and says, that room is so much warmer with the new window.

nealtw is offline  
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
Foundation wall above grade repair MrGazoo69 Bricks, Masonry and Concrete 2 08-11-2011 10:39 PM
wet walls above! ace08 General Home Improvement Discussion 3 03-27-2011 07:25 AM
Foundation inspection measuring tool thing Digger Framing and Foundation 3 06-29-2006 09:49 PM

Newest Threads