> Posted by: "Martha Olson" mbo1955@...
>> Apparently low-E windows are a requirement of the
> code but I noticed they have a solar capture of .28.
> Uncoated windows capture 62% of the sun.
IRC has different requirements for different climates.
Where will you be building? The Low-E windows you
are referring to are for hot climates. Though it is harder
to find, there is Low-E glass available with greater Solar
transmittance. Clear triple glazing is another option.
However, while the current IRC code is like using a
hammer for cutting, it is not totally unworkable. For the
climates where IRC requires U0.35 glazing, direct gain
Solar is not a good idea, anyway. So just reduce the
window area to the code minimum Not only does
direct gain Solar, in those climates, produce uncomfort-
-able temperature swings, it is just plain not very energy
efficient, unless you hang around the house all the time
monitoring Solar gain, and operating window insulation.
In many Zone 5 climates, direct gain windows actually
lose more energy than they gain, during Dec-Jan. If you
want simple, and also efficient Solar heating, your only
option is "Isolated Gain" separating the Solar collection
from the living space, so that the Solar collector glazing
will not lose house heat 24/7. That will get you many
times more Solar heating, from the same glazing area,
and can cost significantly less than a large area of
Isolated Gain, is basically Solar air heaters, which
can be thin panels that 1) Solar heat air, 2) insulate
the South wall, and 3) serve as siding. Or, it can
be a "Sunspace" (sun porch) that 1) Solar heats air,
2) creates a Solar modified environment over the
South wall, and its doors and windows, 3) provides
a roof that serves as a big overhang, over the South
wall, while not reducing wanted Solar heating, and
4) serves as part time living space, as well as an
airlock entry hall.
> Does anyone know of a workaround for this?
I am doing it, right now, for design clients
in Massachusetts and Minnesota.
Natural Solar Building Design and
Solar Heating/Natural Cooling/Energy
Efficiency Consultation Since 1975
www.ThermalAttic.com (many new
photos and pages, coming soon)
Read my Solar house design articles in:
-Energy Self-Sufficiency Newsletter-
Home base-LittleHouses YahooGroup
Founder-WoodGas - Power from wood