Curtains and Other Window Treatments
(On the cheap!)
Pelmet Diagram showing air flow change due to pelmet installation. (Diagram from Energycut.com.au)
As well as curtains the windows need to have pelmets to
prevent air flow between the curtain and the window, as
per the diagram. If not installed this air flow would
result in cooling of the air in winter - and warming in
If the window is full height the curtain should touch the floor in preference to leaving a gap.
I have installed pelmets and curtains on a number of
windows and will complete the rest over the coming month.
It is preferable to have not just single thickness
curtains or even single lined curtains. For greater energy
efficiency it is best to have what can be described as
heavy drapes. I want the drapes to have multiple layers
and a reasonable thickness - too much thickness would make
them too bulky when open.
I looked for ways of obtaining and installing the drape
economically. To get good quality curtains made up is
expensive in Australia (due I imagine to our relatively
high cost of labour). To get the heavy drapes ideal for
energy efficient housing would be even more expensive. I
doubt whether many usual curtain manufacturers would ever
Firstly I owned a couple of curtains that had been used
in my previous house. However these curtains could not be
describes as drapes. They were either single thickness
material or lined - so to meet my requirements they would
have to be added to in some fashion to convert them to my
desired drape. And I only had enough of these for two
windows - I needed more.
As discussed curtains made specifically for the house
would be expensive. However ready made curtains
(undoubtedly made in Asia somewhere) are not that
expensive - especially when on sale. I purchased the
ready made curtains for half normal price at a Spotlight
sale. I then improved the curtains to make them like heavy
drapes by adding detachable linings.
Detachable linings are effectively additional curtains
that are installed behind the curtain facing the room (the
front curtain) by hanging off the same hooks as the front
curtain. You could engage a curtain manufacturing company
to sew them up - for a significant cost - or do it your
self. I decided to do it myself - or more correctly most
of it as will be explained.
I did not have the skill of sewing. I probably could have
taught myself but I didn't have a sewing machine. I
decided to use the services of one of the clothing
alteration/repair shops that you see in shopping centres
for any sewing that I may need. The alterations shop that
I used charged $10 per meter of stitching, so there was
incentive to minimise the amount of sewing needed as much
The first item needed was linings tape. This can be
purchased at Spotlight (though they were out of stock when
I tried to buy some) or Lincraft. This is sewed on the top
of the detachable curtain and provides the means of
hooking the detachable curtain to the curtain rail hooks
behind the front curtain.
For the detachable curtain material itself I used two
layers of bed sheets with a layer of thin wadding in
between the layers. I purchased the wadding from
Spotlight - again it was on sale for half price - $4.30
per sqm.) This would give be a total thickness of four
layers when combined with the front curtain. Why did I use
bed sheets? I had a number spare at the time so they might
as well be used. However I didn't have enough for the
whole house so I had to buy a number of new flat sheets.
The second reason for the use of bed sheets rather than a
more traditional linings material was that on bed sheets
the edges are already hemmed (so I did not have to pay for
hemming at $10 per metre). I bought the sheets I needed
from Target so they were relatively cheap ($15 to $22 for
a double bed flat sheet. Hemming along just one edge of a
lining material would have cost that much.) The size of
the sheet purchased depended on the size of the window to
On reflection I should have used blockout lining
material which would have worked out nearly as
cheap as the sheets - Spotlight were selling it on sale
for $12 per metre - providing I did not have to the get
edges hemmed. The trick is to get blockout lining material
with a width greater than the drop of the the curtain
required. This is so you don't have to join (sew) lengths
of the blockout material together. This material is not as
readily available as lesser width material but it is
around. The blockout material would also probably work
better in terms of insulation. The blockout linings
material is coated with a backing material (rubberised?)
consequently when the material is cut the edges do not
fray so providing you cut straight (rule a line as a
guide) and cut carefully you can get away without hemming
the material - remember it will be behind the front
curtain so will not be readily seen. Or you can get them
hemmed - it would ad $50 to $70 per curtain set per
window, so still not expensive. This would still allow the
use of multiple layers -
blockout | wadding | blockout
- with the blockout is wrapped around the wadding
material to protect it - as per the instructions below.
However, while I think that this would work fine I
don't know how bulky the linings would be if made like
this. If trying this suggest you try it on one window to
see how the curtains hang.
New Zealand Spotlight was selling a ready made linings
curtain - hemmed blockout with linings tape attached. I
asked locally and they weren't available from Spotlight
There are a couple of factors to consider when choosing
the width of the linings. The lining does not have to be
the same width as the front curtain. It only needs to be
the width of the window plus say a minimum of 150mm. It
can be the complete width but does not have to be for it
to act effectively as a heat restricting lining. Any width
shortness of the lining curtain cannot be seen behind the
front curtain. This assumes that the curtain rail extends
beyond the width of the window side architraves, which
they should to allow the curtain to reveal the full window
when the curtain is open. So the size depends on this plus
the size of the bed sheet if used. If using blockout
lining material might as well make the linings the width
of the curtain when open plus 100mm - 150mm. The height of
the lining should be the height of the front curtain to
the curtain rail hanging hooks.
The steps are:
The arrangement outlined will provide superior
thermal performance compared to simply lined
The other advantages are the low initial cost (a bit over
$100 for the lining curtains for a 1.8m wide 2.1 high
window - add $70 if hemmed) and if it was ever required
that the curtains be changed then just the front curtain
could be changed. The detachable lining can be reused. Or
if the detachable lining has degraded due to solar
exposure it can be replaced or repaired separately to the
If the curtain has to stop direct solar insolation, that
is the sun shining through the window into the room then
blockout material (and not sheets) needs to be used. Note
it is preferable that internal curtains not be used to
block out the sun in this way. If sun is shining directly
through the window consideration needs to be given to how
the window can be shaded from the outside so the sunlight
does not directly hit the window in summer.
The outlined method can be used to upgrade existing
unlined curtains. And even if the curtains are already
lined, a detachable lining can be added to further improve
thermal performance - though there might be a concern
regarding how bulky the curtain and detachable lining
combination is. If this was a concern perhaps leave out
the wadding material - it would still make an improvement.
Or improve them as per the next paragraph.
The other way to improve an existing lined curtain would
be to simply slip a layer (or two!) of wadding up between
the curtain and lining and stitch in place - it doesn't
have to be super neat - it can't be seen easily. Not as
good as adding a detachable lining but still an
One other thing that I tried was that I installed a
spacer - a strip of a couple of layers of wadding -
between the two of the layers of the lining. This was to
try to create an air gap between the layers which adds to
the effective insulation property of the lining. Don't
know how effective this will be.
Anyway I hope this information is useful - as I had never
before made curtain linings I went through a trial and
error process, improving the design with each iteration,
and then finally realising at the end that I should have
perhaps used blockout linings material instead of sheets
for a small cost increase. Lining of curtains is a
relatively cost effective way to improve the overall
thermal insulation of the house. So consider linings, even
if you don't make the linings in the manner suggested in
this article. Any extra layer over the windows will help.
To get the most out of the curtains it is best if they
are sealed as much as possible against the walls and
floors on all four sides.
In terms of priority the curtains should:
(1) Brush the floor;
(2) Be sealed at the sides;
(3) Have pelmets or other sealing at the top.
Do all three if you can - but don't neglect the first
two. These first two are minimal cost.
Brushing the floor with the curtain is just a matter of
ensuring the curtains are hung correctly. There is often a
bit of adjustability in the curtain.
Sealing at the sides is something that is often
overlooked but is very easy to achieve. I just used push
pins and pinned near the top of the curtain to the side of
the pelmet against the wall. Alternatively you could wrap
the curtain around the end curtain rail support to secure
it closer to the wall. At the bottom I used a push pin to
pin the curtain to the top of the skirting board against
If you have children at home may have to use something
more rugged than push pins - even a small screw with a
washer. Some minor damage to the curtain but as the
curtain is not going to be taken down for years this would
not be an issue for me.
Pelmets are an additional cost - which can be lessened if constructed DIY. The cost can be considerably lessened again if so called "invisible" pelmets are installed instead of the traditional pelmets. The commercially available kits use clear acrylic strips so they are nearly invisible however if you are not so concerned with the invisibility aspect then strips of many different types of material could be used such as corflute, thin plywood or even thick cardboard. Paint the same colour as the wall or the architrave to lessen the visible impact.
I did not want to install curtains on the kitchen window.
I was concerned that the curtains would be dirtied too
easily being situated just above the kitchen sink. Instead
I installed a concertina blind (sometimes called a
honeycomb or cellular blind). This window also has an
aluminum roller shutter on the outside. This may assist a
bit with slowing thermal conduction, but it doesn't seem
to seal all that well so I don't know how much assistance
it would provide. The roller shutter was primarily
installed to stop direct solar gains (solar insolation)
through this East facing window on hot summer days, and it
seems quite effective in doing this.
It is preferable for the blind to sit inside the window
frame to allow better sealing around the edges of the
blind. If it has to sit outside the window frame might
have to construct a box around the blind drop.
Also in my case after the blind was screwed into position
there was still a small gap between the top blind frame
and the window architrave. I sealed this with a line of
silicon. Acrylic sealant would also have worked. Should
not need a pelmet for windows with these blinds - unless
it is wanted for appearance.