The best window treatment for any window will take account of a few very practical features..
Does the shape, style and situation of my window help or hinder the design I want to use?
It's difficult to place a modern fabric and curtain style in a traditionally furnished room. So be sensitive to the character of the room.
And most important, how much space is there?
Do you have enough space around your window to allow for your preferred window treatment designs? Deep top treatments work best when there is extra space above the frame.
If you don't want to block too much daylight from entering the room, then you'll need space either side of the window as well. This space on either side is known as 'stackback'.
All hanging drapes need stackback room. The fabric in each drape, plus the lining and interlining if you use it, will need stackback space on either side of the window.
If you don't allow for this, even when your drapes are fully pulled back to either side, they'll cover too much of the window area.
An example of a window in a confined space is one which is right next to a wall. If you need to allow a maximum amount of light into the room, yet you also want to have some fabric at the window, one solution is to have a single curtain right up against the wall.
Note that it's perfectly ok to have a pole butt against the wall on the left without a finial attached.
But you may prefer to have two curtains at the window in order to soften the effect. In this case the best window treatment would be to have a pair of curtains. Of course, you'll restrict the amount of daylight even more.
If you want to really dress the window with a pair of curtains with swags and jabots (tails), then forget about worrying about daylight and go for it! If the room calls for it, use whatever window treatment you like. Remember, the best window treatment is the one you'll be happy with.
Do you plan to use a top treatment such as a cornice box, valance or swags? Here's a general guide for space.
If the total length (from the top of the treatment to the floor) is 8'0" (2.40m) then the average length of your top treatment should be about 1'6". The base of the top treatment should cover the top of the window by 2" or 3" ( cms). So ideally you'll need about 1'3" of space above the window.
This value depends on the thickness of your fabric, the lining, and the thickness of the interlining. For an 8'0" (2.4m) wide window the stackback value could easily be anywhere from 1'0" (30cms) to 1'6" (45cms).
Not so much as you might think.
Modern windows can be successfully treated with traditional styles. I've used grommet (eyelet) headed drapes on Georgian windows. Did it work? I thought so, and the client was delighted with the result.
What's more important is the style of the room. Always select your window treatment designs so they're in keeping with the overall style of your room.
Sunlight and temperature
Does your window get a lot of direct sunlight? Then lining is essential. (I'd recommend you always use lining anyway!)
Does your window let in draughts? Then think about using interlining which is a great insulator, and adds thickness to your drapes. Or if you don't intend using interlining use thermal lining.
Always examine your window, the surrounding area and other factors. If the surrounding space isn't ideal, you may need to adapt your design.