TETON Sports Celsius 0°F XXL review: a warm bed when a winter outage takes the heat

This is a research-based review, based on manufacturer specs and published data. We do not test products. Specs come from TETON Sports' product page for the Celsius 0°F XXL Sleeping Bag, checked November 1, 2026. Cold-weather guidance comes from the CDC and Ready.gov.

The dangerous part of a cold outage is often the attempt to stay warm. Ready.gov warns against running generators near the home, using camp stoves or grills indoors and heating with a gas oven, all carbon monoxide risks. A sleeping bag is the opposite of that risk. It makes no carbon monoxide, needs no fuel and works for as many nights as the outage lasts.

We picked the Celsius XXL because Teton publishes both a survival and a comfort rating, and because the XXL cut leaves room for layers and for a child or pet to share warmth.

Who should buy it

• Households in places where winter outages last days, such as ice storms in the South and Midwest, who do not have a wood stove.
• Anyone who wants to turn off a propane heater overnight. Fuel heaters and sleep do not mix; a warm bag lets you shut it off.
• Larger adults: 90 × 39 in is far roomier than a standard mummy bag.
• People who want one bag that also works as a blanket on the couch, thanks to the two-way L-zip.

Who should skip it

• Backpackers and go-bag builders. At 8.6 lb or more and 21.5 in long when packed, it is a car or closet item.
• Anyone expecting comfort at 0°F. Teton says the 0°F number is the coldest temperature it is designed to keep you alive in, and suggests adding 20 to 30 degrees for comfort.
• Homes that will stay above about 50°F. Teton's 20°F version, rated for comfort around 45 to 50°F, is the milder-climate option.

Strengths

• Honest rating. Teton states the 0°F figure is a survival rating and gives a 25 to 30°F comfort range for this model.
• Room to move. The XXL size is 90 × 39 in, with an integrated hood that keeps heat from escaping at the head.
• Draft control. Teton lists full-length shoulder and zipper draft tubes and an offset-stitch double-layer construction.
• Flannel liner. A 75D polyester flannel lining is warmer to the touch than slick nylon when you climb into a cold bag.
• Two-way L-zip. Opens fully into a blanket; two can be used as a pair on a shared bed.
• Warranty. Teton backs its products with a limited lifetime warranty.

Drawbacks

• Heavy and bulky. Teton lists XXL weights of 8.6 to 11.77 lb across the three ratings and a packed size of 21.5 × 14.75 × 14.75 in.
• Synthetic fill. Hollow fiber makes a heavier, bulkier bag than down for the same rating.
• Weight not split by rating. Teton gives an XXL weight range rather than one figure for the 0°F version.
• Availability varies by color. Teton's own store showed some variants unavailable on our check.

How it compares

The 20°F Celsius is the lighter sibling, and the emergency blanket in a first aid kit is what many households already own. Teton figures are from its product page.

Using it in a long outage

Make one warm sleeping room

Pick the smallest interior room you can, close the door and gather everyone in it. Cover windows with blankets after dark. Put the bags on top of a mattress or a camping pad rather than directly on the floor: cold floors pull heat out faster than air does. Wear a dry base layer and a hat to bed, and keep tomorrow's clothes inside the bag so they are warm in the morning.

Turn the heater off at night

If you heat a room by day with an indoor-rated propane heater such as the Mr. Heater Portable Buddy, shut it off before everyone goes to sleep and rely on the sleeping bags. Keep a battery CO alarm such as the First Alert CO710 in the room either way. Never bring a generator, grill or camp stove inside for warmth, and never heat the home with a gas oven (Ready.gov).

Children, older adults and pets

• Check infants and older adults during the night; they lose heat faster and may not say they are cold.
• Teton's Celsius line also comes in a junior size (66 × 26 in), which keeps a child from sliding around in cold empty space.
• Open the L-zip partway if anyone overheats; sweat makes you colder later.
• Store the bag loose in a closet between seasons and keep the stuff sack for transport.