Hundreds of years ago, people living in Northern Europe discovered that sleeping under a lightweight blanket filled with airy goose or duck down on a frigid night beat huddling under five heavy wool blankets. Americans have since joined the slumber party.

A comforter, or duvet, is a fabric shell filled with down, a combination of feathers and down, hypoallergenic down alternatives or another natural fiber. The shell is sealed and quilted. The more tightly woven the fabric (thread count), the less likely a feather will poke out. Goose down comforters are considered top of the line. Most people slip comforters in protective covers that can also double as a top sheet.

“Nothing beats the comfort of a comforter,” says Nicole Sforza, Real Simple

What’s new?

More down alternatives. There are more choices for those allergic to down and feathers. New alternatives provide lightweight warmth that more closely mimics down.

Ratings. Many companies now provide “warmth ratings” so you can choose a weight and style best suited to your room temperature and body temperature.

Care tips

Air it out. Europeans hang their comforters over their balconies daily. Giving them some sun a few times a year is a good policy.

Store properly. Keep your comforter in a cloth bag to allow it to breathe. Zipping it into a plastic cover could encourage the growth of mildew.

Fluff daily. When making your bed, Sforza says, shake your comforter instead of smoothing it. This keep the filling from clumping in one area.

Follow directions. Many comforters can be washed in the washing machine on the delicate cycle and dried in the dryer on low. Others might require dry cleaning. Follow label directions.

Shop smart

1. Buy a cover for your comforter to keep it clean and dust-free. It’s a lot easier to wash the cover than to wash the comforter. Measure the size of your comforter, as they vary by maker. Sometimes it’s best to buy your covers from the store or manufacturer that supplied your comforter to get the best fit.

2. Down comforters usually have a “fill power” number to help determine the quality and warmth of the comforter. This number, usually between 300 and 800, measures the volume of an ounce of down. Higher numbers mean better warmth.

3. Real Simple magazine road-tested a number of comforters. See results at The most affordable one in their top seven was Ikea’s Mysa Vete, made of duck down and feathers, which sells for $80 for a full/queen.