GBlist: dimar, sunspace

Ann Heidenreich (
Sun, 16 Feb 1997 09:52:16 -0500 (EST)

Thanks for all the advice on windows and sunspaces. No one
responded to my question on the Dimar sawblade. Isn't there anyone
out there in cyberspace who knows where to buy a Dimar sawblade?

Marilyn wrote:

>I really envy you - already starting on your house.
>I have hopes and dreams...

Marilyn, I bought the land 20 years ago and have been hoping and
dreaming and collecting books and materials on solar homes and
ecological living every since ... and all those years living in
Europe and Africa working with citizens' organizations (NGOs) on
environment and development issues not making much money and now
I'm trying to put this house together with family and friends
because it's time for it to happen and all the pieces are coming
together but haven't quite yet and the whole process is amazing and
wonder-ful and a little scary.

Alex Wilson recommended the book Residential Windows by John
Carmody et al which I bought and read and so has Bryan Lee, who is
the contractor/builder of this house. It is very useful (although
I wish it included more on the "A Pattern Language" design aspects
that Mike O'Brien mentioned) and kind of mind blowing. It really
changes the way one thinks about windows (and insulating shades).

On sunspaces, I ordered the Builderguide - Passive Solar Design
Strategies: Guidelines for Home Builders for $50 - and think I
ought to get my money back! So does Bryan. It seems not to
sufficiently take into account the superwindows. Also, none of the
models correspond to what I want to build.

Terry wrote:

>If you plan to grow some houseplants and provide a bright pleasant
>place for a January read go with mostly vertical glass and a few
>skylights. Insulate the heck out of everything.

Yes, this is what I want. A beautiful place that is somewhere
between indoors and outdoors ... like this (I hope this comes out
on your screens):

indoors central space
2nd floor bedroom / \ 2nd floor bedroom
-------------* sun space *-------------
\ /

All the walls are vertical and the sunspace is open over two
floors. The central space in the house is also open over two floors
and framed by a post and beam structure. There are hardly any walls
on the ground floor (28'x40'). The floor is a 4" thick concrete
slab with radiant heat. The upstairs bedrooms open into the
sunspace. The walls will be insulated to R-38, the 2nd floor
ceiling to R-60.

My main questions are, for energy purposes: What is the optimal
area and specifications for the windows on the outside wall of the
sunspace? What is the role of the common wall in determining the
energy balance of the house? Does the common wall need to
incorporate thermal mass and if so, how much? What is the optimal
area and specifications for windows in the common wall? Should the
floor slab extend into the sunspace, or does the sunspace have to
have a separate floor?

Heating is far more important than cooling in this place, which is
in the St. Lawrence Valley near the Canadian border.

If I would follow the Builderguide cited above, the glazing area in
the outside wall would be restricted and the common wall would have
a lot of thermal mass. Bill Paulsen at Accurate Dorwin recommends
using clear, double glazing on the outside wall and double low-e,
double argon, triple-glazing on the inside wall with a thermal
break between the floor and the windows. Terry says, "insulate the
heck out of everything." Does this mean the outside wall, or the
inside wall? Bryan thinks the superwindows should be in the outside
wall and the double-glazing in the common wall.

So what do you think?

Another question: We are planning to use a low-e reflecting vapour
barrier on the inside wall combined with 10" of blown-in cellulose.
If you don't have a barrier reflecting radiant heat, what happens?
In other words, is it redundant to have the low-e vapour barrier
given the 10" of cellulose?


Ann Heidenreich - NGONET
49 Judson St. Apt 2-I
Canton, NY 13617 USA
Tel: 1-315-379-0959

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