Shades of Green

A reader asks The Green Guide:

Hi, I've noticed there is a lot of info on eco-flooring and eco bedrooms and such, but very little on eco- window covering. Is this because there isn't much available? If so, I need to know which is eco-friendlier of these blinds: faux wood blinds, basswood blinds or the regular plastic blinds. What should I look for when shopping for these items? My windows are extra large so they need to be specially made. What environmental questions should I ask the people that come to my house to give me an estimate?

The Green Guide responds:

Before you make any hard and fast decisions about which type of coverings you prefer, it might help you out to know that traditional vertical and Venetian blinds are actually very ineffective at insulating, that is, preventing heat loss in the winter and heat gain in the summer, which means that they have little impact on reducing your energy bill and your overall carbon footprint.

The ability of windows and window coverings to insulate is rated by their R value; the lower the number, the less efficient at preventing heat loss. A standard single-paned window has an approximate R value of 1, and adding Venetian blinds to that window only increases the value to 1.07. By comparison, a bare double-paned window has an R value of 2.

Your best bet, if you're worried about windows leaking cold air this fall and winter, are lined draperies or roller, Roman or honeycomb (sometimes called cellular) shades, installed so that there are few gaps between the wall or window frame. If heat gain in the summer is your problem, wood shutters, preferably external, will do the most to cut your energy bills. But in either situation, you can increase the efficiency of your window by installing low-emittance (low-E) glazing, which you can find at most local hardware stores.

Once you've determined what you want covering your windows, you should begin to look at materials. Faux wood and plastic blinds very often contain polyvinyl chloride (PVC), which has a pretty nasty lifecycle. PVC releases carcinogenic dioxin into the air during manufacture (and after disposal, if it's incinerated), and it contains plasticizers called phthalates, which can trigger respiratory problems and interfere with the body's hormonal systems. In 1996, vinyl mini blinds were also found to contain lead, a neurotoxin used as a UV stabilizer that leaches out of vinyl blinds as they age. The Consumer Product Safety Commission asked the window-covering industry to switch to a safer stabilizer, and now an undisclosed tin compound is commonly used, according to the trade group Window Covering Safety Council.

Shades or curtains made with petroleum-based synthetics, such as polyester or nylon, may be treated with the flame retardant deca-BDE, a member of the PBDE family that could break down into penta-BDE, which has been linked to thyroid problems and learning development disorders in children.

Regarding your question about basswood, shutters made from Forest Stewardship Council-certified wood are the most environmentally sound option, but they're also the hardest to find. American basswood (sometimes called linden) is grown across the eastern U.S., is considered a moderately fast-growing tree and, with the exception of Illinois white basswood , isn't a threatened species. You might not be able to find FSC-certified basswood, but keep in mind that logging companies differ in terms of their harvesting practices, so opt for basswood grown in Michigan and New England states, which have stricter controls on timber companies.

There are a few alternatives to plastic and wood, the most common being bamboo, which has become increasingly popular as a design element over the past few years. Unfortunately, matchstick-style bamboo shades let in a good deal of light and don't provide the insulation of more opaque, synthetic-material shades and blinds.

You'll undoubtedly need to make a few compromises in this situation, as the most eco-friendly material may not always provide the greatest energy-saving benefits. Also, be aware that R values for shades, curtains and shutters aren't commonly advertised, and in some cases, manufacturers may not have had their products tested for R values. A good rule of thumb is to opt for lined, thick shades and curtains; the more opaque, the better.

Blinds/Shades: Hunter Douglas Duette triple-honeycomb shades have a winter R-value of 4.8 when used on double-paned windows (www.hunterdouglas.com, 800-789-0331). Although they haven't been tested for R value, Conrad's Roman window shades, made from natural grasses like flax, bamboo and arrowroot, can be ordered in double-density (which adds thickness) or with an optional cotton or muslin lining, which will add to the blinds' insulation (all shades are custom sized; see www.conradshades.com for dealer and showroom info).

Rapidly growing bamboo is widely available in roman or roll-up shades. Watch out for those treated with conventional stains or finishes that may emit formaldehyde. Calibamboo's 35"x63" unfinished-bamboo woven Roman shades haven't been tested for R value, but their tighter weave will provide a slightly higher insulation and more privacy ($18; calibamboo.com, 888-788-2254). EcoWise bamboo shades in seven colors have a tight weave as well ($74.95 and up; www.ecowise.com, 512-326-4474).

Curtains/Drapes: Draperies made from linen, silk and hemp are fairly common. Green Sage flax/cotton-lined linen drapes are un-dyed and contain no flame retardant treatments ($219; www.greensage.com, 415-453-7915). The same grasses used to make Conrad's shades are used in the company's interior untreated drapes, which can also be lined with cotton or muslin for added insulation (see www.conradshades.com for dealer and showroom info).

Drapery rods: Last but not least, eco-friendly drapery rods can help make up for any compromises you may have had to make with the drapes. The Antique Drapery Rod Co. sells hardware and accessories made from metals with varying degrees of recycled content, FSC-certified wood and bamboo. The finishes they use are all formaldehyde-free and low-VOC, and their packaging is made from recycled plastic. Most of their rods can be attached to fit different window sizes (www.antiquedraperyrod.com, 214-653-1733).