FW: [GBlist] Re: Wood frame windows with high-perf glazing?

[Sarah Holland/David Foley <hollandfoley@acadia.net>]

> From: Sarah Holland/David Foley <hollandfoley@acadia.net>
> Date: Tue, 26 Mar 2002 23:29:13 -0500
> To: Joe Nolan <jnolan@ecovillage.ithaca.ny.us>
> Subject: Re: [GBlist] Re: Wood frame windows with high-perf glazing?
> 
> on 03/26/2002 11:04 PM, Joe Nolan at jnolan@ecovillage.ithaca.ny.us wrote:
> 
>> It's hard to estimate accurately with just RESFEN, but it seems that our
>> energy losses should be cut by at least 10MBTU/yr by using Hurd Insol-8
>> instead of the Andersen duals on our 1800sf 2-story home. Maybe hard to
>> justify as a financial investment, but sounds good to me in ecological &
>> comfort terms.
>> 
>> Feedback welcome.
> 
> Dear Joe,
> 
> First, thanks for being willing to consider more than mere dollars.  Without
> knowing the particulars, I strongly suspect that the best thing you can do
> with windows is to "tune" your glass choices for different faces of the house.
> A slight increase in heat loss for south-facing windows may very well be
> offset by increases in solar gain in winter.  We've just done such an analysis
> for a home we're designing in Maine.  Our preliminary calculations, to be
> tested by computer model, show that if we glaze with double-glazed windows
> with a U value (English) of 0.4 and a solar heat gain coefficient of 0.5 on
> the south, and use triple-glazed low-E windows on east, west and north, we
> will cut 20% off our (already low) backup heating needs for a "base case" with
> Andersen windows, in a 7600 Heating Degree Day (English units) climate.  We
> might do even better with the Hurd products, but possibly not on the south.
> 
> Stephen Twaites, who is on this list and who is a principal at Thermo-Tech
> windows - some of the best windows available anywhere - has reminded us in the
> past that a window that can gain free passive solar heat in a cold climate may
> be more useful than one with a lower U value.
> 
> Best wishes,
> 
> David Foley
> -- 
> Holland & Foley Building Design L.L.C.
> 232 Beech Hill Rd.
> Northport, Maine 04849 USA
> p: (207) 338-9869 f: (207) 338-9859 e: hollandfoley@acadia.net

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