[MassHistPres] More window material
Dennis De Witt
djd184 at verizon.net
Fri Sep 25 15:24:19 EDT 2009
Lee
Such a testing facility was already built and used by Lawrence Berkley
before 2002 See the attached report. Maybe that's what inspired the
one you are referring to. In this case too it would be great if some
PE could just summarize it into a few pages of relatively
comprehensible charts and text. Right now it almost need a PhD in
physics to follow and the conclusions are not summarized out a in
simple accessible form.
Dennis
On Sep 25, 2009, at 3:08 PM, Lee Wright wrote:
> Dennis--
>
> My understanding is that the NT is sponsoring a large study at
> Berkley. I don't recall when it's going to be available, but as I
> recall it wasn't going to be for awhile.
>
> It doesn't seem like it would be that hard for an established
> testing facility to set up and test the various approaches.
>
> I dug up this NPS study last fall . . .
>
> http://www.scribd.com/doc/8167584/Testing-the-Energy-Performance-of-Historic-Windows-in-a-Cold-Climate
>
> . . . but at 175 pages, much of it fairly technical, it's far from
> user-friendly.
>
> Late last year I tracked down the author--he now works for the state
> of Vermont--and sent him a note. I just followed up with him and
> asked him if would be interested in distilling down his report to a
> 1 - 4 page piece that would include a worksheet (or reference an
> online tool).
>
> I'll let you know what I hear.
>
> Best--
>
> Lee
>
> From: masshistpres-bounces at cs.umb.edu [mailto:masshistpres-bounces at cs.umb.edu
> ] On Behalf Of Dennis De Witt
> Sent: Friday, September 25, 2009 2:42 PM
> To: MHC MHC listserve
> Subject: Re: [MassHistPres] More window material
>
> I agree.
>
> What seems to be missing is the alternative of installing high
> quality storms (e.g. Harvey tru-channel) w/ or w/out low-e. They
> should have an infiltration number comparable to the IG replacement
> windows and the U value probably wont be much different than what
> you would see for the typically generic IG used on cheap vinyl
> sash. So, you can spend maybe $150 per window on the storms, save
> the original windows (and maybe spend $150 per window on average
> tightening them up) and not have something that will fail in 20 years.
>
> Why can't the National Trust or the NPS contact this state
> government agency and get them to incorporate storm windows into
> their equation? -- in two places a) factor them in to the "before"
> figure if they already are in place & b) offer them as an
> alternative to replacements for the "after" figure.
>
> Dennis De Witt
> Brookline.
>
>
> On Sep 25, 2009, at 2:06 PM, Michael Smith wrote:
>
>> Our advice to homeowners is to rehabilitate existing historic
>> single pane windows and install new storm windows to gain energy
>> efficiency. This seems to be a common suggestion in much of the
>> literature on historic window restoration. Comparing the
>> infiltration rate of an old wood window with that of a new
>> insulating glass, energy-efficient window, without factoring in a
>> new storm window seems inconsistent with most recommendations. Or
>> am I missing something?
>> Michael Smith, Co-Chair
>> Belmont Historic District Commission
>> From: Chris Skelly [mailto:Skelly-MHC at comcast.net]
>> Sent: Friday, September 25, 2009 1:57 PM
>> To: masshistpres at cs.umb.edu
>> Subject: Re: [MassHistPres] More window material
>> I think making any assumptions on the "infiltration" factor of an
>> old window demonstrates that this worksheet is misleading. Just
>> because a window is old doesn't mean it has to leak air.
>> Would we use this logic to demonstrate how much money we would save
>> by buying a new car? If comparing how much money you would save
>> on automobile fuel, you would need to consider the miles per gallon
>> of the old car and the miles per gallon of the new car. All old
>> cars don't have the same miles per gallon and all old windows
>> shouldn't be treated with such a broad brush either. Furthermore,
>> the infiltration that will occur over time with a new vinyl
>> replacement that warps and bends needs to be factored here as well.
>>
>> When it comes to saving energy on heating a home, infiltration is a
>> major issue that needs to be addressed. Yet when it comes to
>> old wood windows, infiltration can be addressed very effectively
>> through a number of methods. Methods such as installing removable
>> rope caulk each fall are very inexpensive. For those on a tight
>> budget and faced with leaky windows, this can make a huge
>> difference. Chris.
>> Christopher C. Skelly
>> Director of Local Government Programs
>> Massachusetts Historical Commission
>> 220 Morrissey Boulevard, Boston, MA 02125
>> Ph: (617) 727-8470 / Fax: (617) 727-5128
>> Christopher.Skelly at state.ma.us
>> http://www.sec.state.ma.us/mhc/mhcidx.htm
>> *******Stay Informed on Historic Preservation Topics by joining the
>> MassHistPres Email List. Visit http://mailman.cs.umb.edu/mailman/listinfo/masshistpres
>> for more information. ******MHC offers regional training workshops
>> to local historical commissions and historic district commission
>> members on a variety of topics. ******The MHC has a new 50 minute
>> DVD for Local Historical Commissions. ******The Local Preservation
>> Update is MHC's new bi-weekly e-newsletter. For more information
>> on any of the above, please contact me.
>>
>> -----Original Message-----
>> From: masshistpres-bounces at cs.umb.edu [mailto:masshistpres-bounces at cs.umb.edu
>> ]On Behalf Of slater at alum.rpi.edu
>> Sent: Friday, September 25, 2009 12:04 PM
>> To: masshistpres at cs.umb.edu
>> Subject: Re: [MassHistPres] More window material
>> Maybe someone can help me out here. I just did this worksheet for
>> window replacement:
>>
>> http://www.dnr.mo.gov/forms/780-1363.pdf
>>
>> Based on my calculations, it told me that a house with 30 single
>> pane windows with storms will consume 582 gallons of oil -- just
>> for the windows -- and that if you install low-E replacements, it
>> would consume just 233 gallons of oil just for the windows.
>> Replacing would save 439 gallons of oil annually.
>>
>> Let me tell you my assumptions and maybe someone else can try this.
>>
>> First, I assumed 30 windows at 32" x 62" -- each being 13.9 square
>> feet. That's about the size of my second floor windows. Multiplied
>> by 30, that's 417 square feet of windows.
>>
>> Second, I used 0.5 U-value for single pane with storms, 0.38 for
>> double-pane with low-E glass. That's an agreed upon number.
>>
>> I used the "degree days" method in line 6, since this form is for
>> Missouri and we are in Massachusetts. The calculation says "degree
>> days x 24 / 10^6". I used 6250 degree days, a number I got from an
>> energy website. That changed the factor to 0.15 versus the 0.1 for
>> Missouri.
>>
>> I used an energy cost of $19.73 per million BTUs. That was based on
>> oil being $2.75 per gallon. It came from this website:
>>
>> http://energy.cas.psu.edu/costcomparator.html
>>
>> I treated the fuel efficiency as 100% in the calculation because
>> the energy cost from the previous step already factored that in.
>>
>> I assumed that a vinyl replacement window costs $300 installed.
>>
>> Using the formula on the spreadsheet, it said that if I keep the
>> original 30 windows, I will spend $1,849 in heating costs, and if I
>> replace them, I will pay $641 in heating costs.
>>
>> If that's true, that seriously weakens the argument for keeping the
>> originals pretty significantly -- if a replacement window costs
>> $300, then payback period is just 7 years. If oil goes up by 45% to
>> $4/gallon, then the payback period is just 5 years.
>>
>> One big factor is that the calculation uses something relatively
>> new (it wasn't on an earlier version of the form) called an
>> "infiltration factor". It is set to 1.00 for old windows, 0.14 for
>> new windows. That seems a little arbitrary, and it completely
>> changes the results of the calculation. Without this factor, a
>> replacement window without low-E glass is actually less efficient
>> than an original window with storms.
>>
>> I did some research on "low-E" -- there is some thought that it
>> does not last for the life of the window, and may only last for 5-6
>> years before breaking down.
>>
>> Can someone else validate my numbers? Honestly, they are just not
>> that believable. I have 49 windows in my house -- some of them are
>> quite leaky, such as leaded glass casement windows -- with storms,
>> though the leaded glass transoms above them don't have storms. I
>> also have several windows without storms -- two 2nd floor bathroom
>> windows and a casement window over the kitchen sink, plus a fixed
>> window with multiple lights, plus a couple of 3rd floor casements
>> that open inward. Many of my windows are larger than the example I
>> used too.
>>
>> I use about 1,200 gallons of oil per year to heat a 4,000 square
>> foot house to around 65 degrees. If I plug 50 windows into to this
>> worksheet, it says 1,100 gallons of that is due to the windows, and
>> I would save 718 gallons per year by replacing them.
>>
>> I just can't believe that on its face. Could these calculations be
>> designed to justify replacement?
>>
>> Ralph Slate
>> Springfield, MA
>> ******************************
>> 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/20090925/583e5ee1/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Window tests results JH Klems.pdf
Type: application/pdf
Size: 349909 bytes
Desc: not available
URL: <http://mailman.cs.umb.edu/mailman/private/masshistpres/attachments/20090925/583e5ee1/attachment-0001.pdf>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.cs.umb.edu/mailman/private/masshistpres/attachments/20090925/583e5ee1/attachment-0003.htm>
More information about the MassHistPres
mailing list