[net.general] Energy Efficient Window Design Contest

dkatz (01/05/83)

NEEDED - Ideas for reducing heat loss through windows.

As you ALL know, the major loss of heat from an energy efficient house
(not counting what goes up the chimney) is radiant loss from the windows -
particularly at night.

I am planning to build a new house and am looking for ideas on how to prevent
this.  Suggestions found so far are:

1.  Curtains
	only minimally effective.

2.  Shutters
	- indoor shutters move through usable floor or wall space and are
	  therefore undesirable.
	- outdoor shutters!!!  Who wants to go outside at -40 degrees to
	  close the shutters.
	- outdoor shutters controlled by mechanical devices indoors tend
	  to freeze up, and require special care in the design to prevent
	  infiltration around the mechanism
	- outdoor shutters motor driven and controlled from indoors tend to
	  freeze up and are EXPENSIVE

3.  Heat Blinds
	still not very good because air circulation around them still permits
	large heat loss.  Also, the glass is to the outside while the blinds
	are closed, and therefore tend to collect moisture => wood rot, and
	humidity problems.  This is also true of indoor shutters.

4.  Plexiglas
	Turns cloudy under UV radiation

5.  Window glass separated by about 2" of air and filled with styrofoam beads
    blown in at night
	Increase heat loss during daylight hours when evacuated
	EXPENSIVE, not even within reach for other than picture windows
	High maintenance level

6.  Multi-pane glass
	marginal improvement, loss of solar benefit during day, coloration
	and distortion

7.  No Windows
	Against the building codes

Any Suggestions would be greatly welcome.  The winner gets a free copy of
the architectural detail drawing showing the method used (what more could
you ask for?)

Respond by electronic mail please.

:-{  Freezing Face

Dave Katz