Changing home window treatments might only seem like a change in decoration, but it can also become a good way to make a change for the environment. You also might be thinking, wait, what’s wrong with my windows and why do they need treatment? “Window treatment” is just the term for all window coverings, whether they are curtains, blinds, shades or anything else you use. Most likely there is something to improve with your windows, though. Regular curtains and drapes do a good job blocking sunlight and reducing some heat loss, but only by about 10%. This is because they are primarily designed to block the direct light and offer privacy but not generally made for insulation or energy efficiency. By making a few small changes and switching to a more effective window treatment, you can help save much more energy and also gain some home comfort.
Heat Blocking and Light Filtering
During the summer season when the sun is strongest and temperatures can reach triple digits, the important thing is to have window coverings that block out the light and keep heat out. In the cold winter, the opposite is true and window coverings that let light filter through are needed for solar heating and natural lighting. Average drapes or blinds can accomplish either of these by adding a room darkening lining or using a sheer fabric instead. The essential element missing in either of these cases to get true energy saving is insulation that will control the heat exchange and maintain the temperature to keep home cooling and heating usage to a minimum.
Insulating and Heat Exchange
The problem with standard window coverings is that they have gaps around the edges and are loosely fitted far from the window glass so that heat is free to easily pass through. This is why it’s important to have properly measured and custom fitted window treatments if possible, rather than using readymade style shades. An R Value is used to measure insulation in window coverings. Standard shades have an R1 value. Specially lined curtains and cellular shades can have an R6 value.
Cellular shades are composed of pocket-like fabric cells, which resemble a honeycomb from the side, and keep convection currents from transferring heat into a room. The insulation value between single and double layer honeycomb shades generally ranges between R2 and R5. They can block about 60% of heat transfer from the window. There are some specially designed cellular shades that have cells layered inside of other cells and can achieve an insulation value past R7.There is also a line of cellular blinds that expand and collapse individual fabric vanes for visibility, but maintain the same insulating properties with their honeycomb design when expanded.
If you don’t want to switch to cellular style shades there are still some things you can do to improve other window treatments using the same principles. When installing curtains, make sure to let them hang all the way to the floor and have a tight fitting top treatment to trap the air behind the drapes. Individual shades also generally perform better at insulating than curtains because they can be installed very close to the window glass and fitted with sidetracks to form a tight seal, which can cut heat exchange by up to 45%. Use light colored fabrics to also help reflect light and heat during the summer. Between horizontal and vertical blinds, the horizontal style is slightly better at letting light in and blocking out heat. West facing windows will receive the most heated sunlight, so pay special attention to these.
The best idea is to combine window treatments with layers and to use both interior and exterior coverings. Shutters, screens and awnings can all be used on exterior windows to effectively reduce heat exposure. South side facing windows are the best choice for directing natural lighting. Use a layer of Solar screen shades here, which will block much of the light, including harmful UV rays, but still let some light pass through and preserve visibility out the window.
You’ll need to get new window treatments eventually, so consider taking the initiative now and start saving energy today. There are recycled and chemical free fabrics also available to consider for a healthier and more environmentally friendly living space.
Tom Vatury has been specializing in the window treatment industry for over 10 years and is a writer for windowtreatmentstalk.com