Well fitting curtains can cut heat loss and gain by trapping a layer of still air next to the window. Window furnishings are good way to deal with problems with existing windows. Heavier fabrics and multiple layers of fabric give the best thermal protection.
The importance of pelmets in heating and cooling is generally not recognized; in fact they can reduce both heating and cooling bills. Guess you thought they were just for show. How do they work though?
During an Australian summers day the outside temperature usually continues to rise well above the temperature inside the house. As the mercury goes up the heat outside will try to move through the windows into your home. The outside air warms the window glass and then the inside air which is in direct contact with the glass. As the inside air is heated it rises and make its way into the house.
Normal or poor fitting curtains cannot block this warm air and stop it entering the room. But a pelmet effectively prevents rising air moving up from behind the curtain into the room. So you reduce the cooling needed in summer.
But what about winter? In summer we want to keep that hot air out – in winter it’s the other way – we want the warm air inside. When you warm inside the room during winter it heats the inside air which rises to the ceiling and convection begins. As the warm air cools it begins to fall back to floor level and part will make contact with the window glass. Try touching the glass when it’s cold outside, so air touching that cold glass gets colder.
So this time pelmets prevents the inside warm air coming into contact with the glass. This prevents the heat loss which would happen otherwise through the window.
So a pelmet is a barrier to keep summer hot air out and warm air in during winter!
Good curtains and pelmets will help improve comfort and reduce energy costs. Fitted pelmets reduce heat loss above windows. Pelmets can be made of any material as long as it creates an air barrier. If you rent make temporary pelmets from cardboard or other stiff materials, bubble wrap or even a thick piece of fabric. Pelmets only need to be against the wall and reach to or past the curtain. Most pelmets reach over the curtain. However you can also build a hidden or near-invisible pelmet as a single flat strip that sits behind the top of the curtain and just reaches its back edge.
How to make a simple Box Pelmet
Lengths of 6-8mm MDF
50mm chipboard screws
Wall plugs and fixings, brackets etc (brick walls equals dynabolt or similar)
Sand paper paint or go the whole hog and cover with fabric.
1 To find the overall width of the pelmet, measure window opening and add at least 100mm oo each end so curtains can be drawn back without creasing. Depth should be distance from the wall to the front of the curtains plus at least 30mm. If possible get the Hardware store to cut the wood to the length, but you will still be cutting. If the hardware store hasn’t cut the board remember measure twice cut once.
2 Cut out front piece of the pelmet. A portable workbench with a clamp will help when you cut.
4 For the top of the pelmet, use another MDF length cut to fit inside the front of the side pieces. Fix with more 50mm (2in) chipboard screws and glue.
5 Paint or otherwise decorate the pelmet box.
7 Hold pelmet in place, use the spirit level at the top and mark through bracket fixing holes when it is level.
Now Pelmets are a really useful solution, but in Australia many homes will benefit from a pergola (with some greenery on it) or sun blinds (the lighter the color the more heat they will deflect. If you are on a tight budget (or if you are renting) removable Aluminium reflectors will make an enormous difference.