Does window film keep the cold out?

 We have single-pane windows, but we don't want to spend $10,000 for
new ones. One alternative we're considering is putting down window
film. How effective is it at reducing heat loss? Does it block a lot
of natural light?

  Not really. Tho its actually the heat in the room going out, not the cold coming
in.

skybearer@gmail.com wrote:


Not very.

 skybearer@gmail.com wrote:


What kind of window film, and what kind of installation?

There are MANY window films, from cheap polyethylene that you tack/tape to the
frame as an attempt at a storm window, to self-adhesive films that you apply
directly to the glass to reduce radiant heat transfer.

If your old window frames are not well insulated and installed, you will not
see much benefit from any film.  If the frames are tight, though, a heavy-grade
plastic in a "storm window" type installation will help somewhat.  Without cold
wind and rain directly on your window glass, convective losses will be reduced.



Again, it depends on the type of film.  Cheap polyethylene is only translucent,
so you won't be able to see well through the windows.  The radiant barriers
block a significant amount of light, but the better ones are essentially
transparent, so you can see well through them in the day time.

 I have film on my shop windows, and it seems to block most of the infrared
heat rays from the afternoon sun.  It blocks about 20% of the visable light
in the process.

As far as keeping heat inside, in cold weather, ya, it helps, but only a
little bit, and not enough to justify the expense.
You'd probably be much better off if you caulked around your windows real
well, and put up some extra heavy draperies over the windows.

When I owned a house, I'd put some sheet styrofoam over the windows that
didn't face the street, and also on the metal front door.   It was cheap,
and simple to do, and cut heat loss enough to pay for itself.   But, it also
made things fairly dark inside -- but that didn't matter much, as I was
working nights at the time, and slept during the day.

 


  As others have said, I wouldn't expect film applied to the window glass to
reduce heat loss much at all. If your windows would look good with
double-cell "honeycomb" window shades with minimal air gap between the
window wall/sill and the shades, they can help reduce winter heat loss quite
a bit and be much cheaper than new windows. A plastic film or sheet applied
inside or outside the window frame with an air gap between it and the pane
will help, but I wouldn't want to leave it up all summer long--and the
effort of installing/removing it annually would get to be a real pain. If
you go with the double-cell shades, wait until your local department store
has a sale on them. JC Penneys, for example, generally offers "65%"
discounts on custom shades at least once a year.

Craig