Monday, March 8, 2010


I had been trying to find a new construction window with a low U-Factor when I found SeriousWindows.

The typical new construction window is vinyl, double pane and filled with argon gas.  Finding the energy efficiency of windows is tough for both the builder and the consumer.  So what are U-Factors and how do they compare with R-Values?

R-Value is a standard measure of heat loss through a partition, such as a wall, window or door. In the past, while the insulating performance of walls has been measured in R-Value and windows have been measured by U-Value.  The use of U-value makes it harder for builders and homeowners to see the poor R-Value performance of major brand windows because who the heck knows what it means! 

Most new construction windows have a U-Factor of .30 - .27 (lower is better).  That equates to an R-Value of 3.3 – 3.7! Ouch! The standard wall the window sets in has an R-Value of 11!          Guess where your heat is going?

Serious Windows, Inc has introduced a Series 1125 fiberglass window with triple suspended film and filled with Xenon gas, a U-Factor of .09 (WOW!) and an R-Value of 11. This is just what you need to fight those high utility bills but there is a downside….the cost!

Serious Windows

Rumor has it, and that’s all I have to go on since they don’t publish a price list, is that their 1125 Series windows sell for  $2,000 – 2,200 each!  Ten windows in your new home would cost over $20,000 with SeriousWindows while ten Pella ProLine windows would cost only $4,000.  Even adding insulated shades to every window would only add another $2,000 to 3,000 for a total cost of $6,000 to 7,000, a savings of $13,000! 

You have to ask yourself if having the best window money can buy to give you a better Energy Star Rating in your new is really worth it.  Maybe it is but you better be prepared to live in your home for a long , long time.


Barry E. LaDuke said...

Serious Windows seems to have borrowed technology originally developed by Southwall Technologies called Heat Mirror (TM). Back in the late 80's I used to run a crew in Kent, WA that made Heat Mirror glass for the Boeing Flight Museum, Lindal, and other such customers.

The economic assessment you made for this product was true for Heat Mirror as well. I speculate that cost is the reason you don't hear much about Heat Mirror anymore.

I wonder - did the patent on Heat Mirror run out so that Serious Windows could develop their own film?

Harris Woodward, CGP said...

I priced Serious Windows last fall and they are UP there:

ONE Series 725 (not 1125) 36x56 doublehung was $1444. This was from a distributor in Lancaster, PA.

We then modeled its performance against an Andersen 400 DH with the upgraded glass at approx $300.

Results? You have to live in that home a LONNNNNGGGGG time to see an ROI here in semi-temperate Maryland.

Maybe in Alaska, and maybe with window companies in Canada (who are HALF as much as Serious windows with just a bit more freight).