There are many factors to consider when selecting and installing window coverings since they are such an integral part of a home or business.. Aesthetic requirements of blinds or drapes need to work in conjunction with important practical functions.
Some of the key elements when selecting window coverings are going to be cost or budget considerations, how the window coverings can provide privacy, the protecting of other furnishings from sunlight damage, reducing the amount of noise coming in from outside, saving energy costs, and finally ease of maintenance including regular professional cleaning.
In terms of price, it is standard practice to spend more on show rooms or public rooms than on work or relax areas. Keep window coverings the same or at least coordinated on each floor to keep the appearance of a home or building consistent when being looked at from outside.
Allowing natural light into a living or working space is beneficial to people and throws a warmer and more accommodating cast on everything in a room. To maintain privacy but still have some 
natural light coming in consider the use of sheers.
Window coverings can reduce 5-15% in energy costs and this is helped by having sheers behinds drapes, or with lined drapes that help hold heat in. Window Coverings also work to keep a home cooler in summer and they can make a home more comfortable by reducing drafts. Otherwise open drapes and blinds at some point each day to allow for greater air circulation and to reduce moisture build-up.
Windows facing south and west need special attention because they face most of the sunlight. In particular keep these windows open more in winter to allow sunlight to enter and provide warmth while reducing the energy bill. Closing these blinds and drapes at night then helps to keep the heat in. Consider the material and warranty for these window coverings as they will be subject to the weakening and damaging effect of sunlight.
Horizontal blinds best keep heat in and cold out when the inside is closed facing upwards. The closer window coverings are to the window, the more effective they will be as an insulator. Hanging curtain rods as high as possible in a room elongates the room and make the ceiling appear higher while increasing their insulation value.