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When the temperature drops, every degree you turn down the thermostat below 70 saves you a whopping 320 pounds of greenhouse gas emissions if you have natural gas heat and 236 pounds if you have electric heat. But dropping the thermostat temperature is a lot more comfortable if you're curling up in bed under a mound of blankets—preferably ones that aren't made with petroleum-derived synthetic fabrics.

Fortunately, eco-friendly alternatives seem to be cropping up everywhere we turn. No longer is it just for the wealthy or those greener than thou, as commercial retailers like Bed, Bath & Beyond, Pottery Barn and West Elm now offer their own certified organic cotton bedding, which is better for the planet and healthier for you.

Organic cotton isn't your only option. Ingeo is a trademarked synthetic fiber made with dextrose derived from plants like soybeans and corn. Hemp fiber is even warmer because of its heavier weight and hollow core, and it's naturally antibacterial. Pure Grow Wool, which originated with a co-op of sheep ranchers in Sonoma County, Calif., comes from sheep that were raised humanely and without the use of pesticides. Wool wicks moisture away from your body, and it regulates your body temperature, keeping you warm in the winter and cooler in the summer.

Or combine substance and style with an antique quilt. Although expensive (depending on the age and quality of quilts, they can range from $100 to upward of $3,000), they're great keepsakes and require no new resources to make. The Antique Quilt Source (www.antiquequiltsource.com), located in Lancaster County, Penn., constantly receives new stocks of quilts from as early as the 1800s. If you're planning to use an antique quilt on a daily basis, opt for cotton over silk and a younger quilt over an older one, says Glenda Strong, the Antique Quilt Source's owner. To maintain the quilt's lifespan, she recommends washing it by hand with a mild detergent (as long as the fabric is color-fast), because spinning washing machines can damage fragile materials.

GG Product Picks

West Elm organic cotton knit throw ($49; www.westelm.com, 888-922-4119)

Pottery Barn organic cotton waffle-weave blanket ($69-$89; www.potterybarn.com, 888-779-5176)

EcoChoices Super Soft Brushed Organic Cotton Blankets ($129/twin; www.ecobedroom.com)

ABC Carpet & Home woven organic cotton throws in ivory or beige ($150/queen; www.abchome.com, 212-473-3000)

Coyuchi Jacquard organic cotton blankets dyed with Control Union/SKAL-certified heavy-metal-free dyes ($132-$225; www.coyuchi.com, 888-418-8847)

Natural Living Shop Ingeo fiber comforter ($99; www.amazon.com)

Rawganique 100-percent hemp comforter ($378/twin; www.rawganique.com, 877-RAW-HEMP)

EcoChoices Pure Grow wool blankets ($279/twin; www.ecobedroom.com)