[MassHistPres] Fwd: a question on historic windows

[Nancy Dole]

Thanks so much everyone for your help. Much appreciated! 
Nancy Dole
West Tisbury HDC

On Apr 17, 2013, at 9:32 AM, "Scott A. Winkler, AIA" <swinkler.architect at gmail.com> wrote:

> The Residential Building Code allows for compliance with the energy efficiency requirements using several methods.  The easiest and most common method of determining compliance is following the "Prescriptive Package" which gives specific minimum standards of insulation required for each of the building components (walls, roofs, windows, etc).  This standard requires a maximum U-factor for windows of 0.35 (u-factor is the inverse of the more familiar r-value, and lower is better)  The windows need to carry a NFRC (National Fenestration Ratings Council) rating label showing that they comply.  Windows made my a small manufacturer or millwork shop will likely not be able to provide this label.
> 
> For someone looking to get creative with a new building (installing historically correct windows) they will need to utilize one of the other methods of compliance.  They can utilize the REScheck software which is available for free on the U.S. Department of Energy's website.  In this option, they input values for all of the building envelope components (including windows) and the energy efficiency of the building as a whole is analyzed to determine if the building complies.  In this scenario, one could use less efficient windows along with higher efficient walls/ roof to comply.  There is also credit given for more efficient heating systems, etc.  If you end up using windows that do not carry a U-factor rating, the building code will allow you to utilize a default number in your calculations, which is spelled out in the code (0.89 for single glazed wood windows).  Unfortunately, the code does not specifically give credit for storm windows over single divided light windows.  There is a way to calculate this, which is a bit more complicated.  You might be able to convince your local building official to allow you to use the default value for double glazed wood windows (0.55) in your calculations.
> 
> So... The answer is yes, you can use true divided light windows, if you offset the energy loss with other improvements and spend the time to prove it works.
> 
> Scott A Winkler, AIA, LEED AP
> 
> 
> On Apr 12, 2013, at 11:04 AM, Nancy <ndole at verizon.net> wrote:
> 
> > Can anyone address this issue? Thanks,
> > Nancy Dole
> > West Tisbury HDC
> >
> >
> > Begin forwarded message:
> >
> >> From: Sean Conley <nautilus at vineyard.net>
> >> Date: April 11, 2013, 4:53:11 PM EDT
> >> To: Nancy Dole <ndole at verizon.net>
> >> Subject: a question on historic windows
> >>
> >> Nancy;
> >>
> >> A man named Brian Beale called me.
> >> He is trying to build a new house in WT in the manner of a historic house, (Not in the District)
> >> He says the new building energy codes will not allow him to use true divided lights.
> >>
> >> He was wondering if we knew any appropriate windows that could work.
> >> As I knew that you had done so much research on windows,
> >> I gave him your name and home number.
> >>
> >> Let me know if he calls.
> >>
> >> Yours, Sean
> 
> -- 
> Scott A. Winkler, AIA, LEED AP
> ******************************
> For administrative questions regarding this list, please contact Christopher.Skelly at state.ma.us directly.  PLEASE DO NOT "REPLY" TO THE WHOLE LIST.
> MassHistPres mailing list
> MassHistPres at cs.umb.edu
> http://mailman.cs.umb.edu/mailman/listinfo/masshistpres
> ********************************
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.cs.umb.edu/mailman/private/masshistpres/attachments/20130418/868bcd3c/attachment.htm>