Edwin Pawlowski wrote:

"Sawney Beane" wrote in message


On a cold night, what's a good way to reduce heat loss through
the windows? Do the blinds make much difference?

Everything helps, but heavy drapes will do more than the blinds.

If you can stop convection, that's probably like adding R-1.
One winter in Vermont, relatives warped their wood stove
running it red hot, but they were still miserably cold. The
problem was their single-pane picture window. We sewed a
curtain of bedsheets, stretched it across the window each
night, and secured it with thumb tacks. The cabin was much
more comfortable and the stove could be run low.

I don't know if heavy drapes would have worked as well. They
don't necessarily stop convection.

A reflective surface can make an airspace with an R value much
higher than 1. I have fixed windows for winter by gluing
foil-faced kraft paper across them, but you can't look out
until spring. I've also made curtains of printed bedsheets
with space-blanket backings. As I recall, I used rubber bands
in buttonholes to stretch the curtains tight across the window
ledge at night, to stop convection. Rooms with those curtains
were much warmer than winter than rooms with other curtains.

I was looking for more tips on efficient curtains, blinds, and shades.



In summer it can pay to reflect sunlight hitting east and west
windows. Vinyl blinds let some light through and probably
absorb some. Is there a better way to reduce solar heating
through windows?

In the winter you want to let that sun come in as much as possible. Thee
are coatings that will help in the summer though.

Generally, it's the south windows that get solar heat in
winter. The sun that shines from east and west is low and
southerly, so those windows don't pick up much.

In summer, the sun is higher and spends a lot of time on the
east and west, so those windows can pick up a lot of heat.
The summer sun may be too high for much of its heat to shine
through the south windows. So I'd come out ahead if I could
make my east and west windows reflect more sunlight, but not
my south windows.

Some reflective coatings can also reduce radiant losses at
night. I wish I knew more about it.