Buyer's Handbook
Sleeping bags and pads, and a warm night when the house is cold.
A good sleeping bag earns its shelf space twice: on a camping trip, and on the night the furnace stops. This handbook explains what the temperature numbers really mean, why the pad underneath matters as much as the bag, which kind suits your household, and how to stay warm at home without making the heat itself the danger.
Reviewed November 2026. We re-check this guide quarterly.
By Dan Whelan, founder of New World Survival
Researched from government agencies, university extension services, and other published sources. See our sources
Start here
The second night without heat
Picture an ice storm that takes the power out on a Tuesday. The first night is fine; the house holds its warmth and everyone piles on blankets. By the second night the thermostat reads 50 degrees, the bedrooms are colder than that, and the question becomes how the family sleeps warm until the lines are fixed.
A sleeping bag on a good pad answers that question quietly, with no fuel and no flame. The same bag goes camping in the summer. The catch is that the number printed on the bag is easy to misread, and a bag on a bare floor is far colder than its label. This guide covers the numbers first, then the gear, then what to pay.
Before you buy
Five questions about how your household sleeps
Answer these before you look at a single product. They decide how warm a bag you need, which pad goes under it, and whether the bedding you already own is most of the answer.
Where will it be used most?
At home if the heat goes out, kept in the car for winter driving, or on camping trips. A bag that lives in a closet and comes out twice a year has different needs than one carried on your back. The insulation and shape section matches each one.
How cold are the coldest nights you would use it?
Not the average night. The coldest one you can reasonably expect, indoors or out. That single number, compared against the right rating on the label, does most of the choosing. The ratings section explains which rating to read.
Does each person sleep warm or cold?
People in the same house can need very different bags. The lab ratings come in two numbers for exactly this reason, one for cold sleepers and one for warm sleepers.
Who in the household needs one?
The ISO rating standard covers adult bags only. Children need a bag sized for them, and babies should not sleep in an adult or camping sleeping bag at all. The safety section covers both.
What does a sensible start cost?
Possibly very little. For a night at home, the comforters and blankets you own plus a foam pad on the floor go a long way. When we checked in November 2026, a closed-cell foam pad was about $50, rectangular synthetic camping bags rated 50°F to 20°F ran from $59 to about $120 at REI, a wool blanket ran from about $40 to $228, an insulated air pad was about $200 to $240, and a premium down bag rated into the teens listed at $399. The full ladder is in the what to buy section.
How it works
You are the heater. The bag only keeps it in.
A sleeping bag makes no heat of its own. Its insulation traps still air around your body, and still air is what slows the heat you produce from leaving. Thicker, fluffier insulation traps more air, which is why makers talk about loft.
That loft has a weakness. When you lie down, your weight crushes the insulation underneath you nearly flat, and the cold ground or floor pulls heat straight out of your back. A sleeping pad is what stops that. It is half of a warm night, not an accessory, which is why REI advises thinking of the bag and pad as one sleep system.[3]
The lab ratings on a bag assume a pad is there. REI notes the testing places a sleeping pad under the bag and dresses the test dummy in base layers,[2] and REI's sleeping bag guide says ratings assume a pad of about R 5.5,[3] and its sleeping pad guide says R 4.[17] On a thin pad, or straight on a cold floor, the same bag will feel much colder than its label.
The distinction that matters most
The number on the bag is not a promise
A bag called "20" is not guaranteed to keep you comfortable at 20°F. Which number you read, and whether it came from a lab, decides whether you sleep well or lie awake shivering.
What the lab rating is
- The current standard is ISO 23537-1:2022. It covers adult sleeping bags for sports and leisure use with a limit temperature of -20°C (-4°F) or warmer, and it does not apply to bags for children or babies, or to military and extreme-cold expedition bags.[1]
- Some older bags carry a European EN rating instead. REI says the two tests are similar enough that an older EN-rated bag can be compared with a newer ISO-rated one.[2]
- Most brands now have an independent lab run the test, which is what makes ratings from different brands comparable.[2]
How labels mislead without meaning to
- The number in a bag's name is rounded. REI gives the example of a bag named "15" whose tested lower limit is actually 18°F, and says there are no fixed rules for which way brands round.[2]
- A rating not labeled "comfort" or "lower limit" is probably the brand's own estimate, not a lab result.[2] Many inexpensive camping bags carry only a single "temperature rating."
- Brands may skip lab testing on bags meant for mild weather or casual use, and the test is not valid for kids' bags or bags built for extreme cold.[2]
| Rating on the label | What it means | Read it if |
|---|---|---|
| Comfort | The temperature at which a cold sleeper might feel comfortable. Brands use it on women's bags.[2] | You sleep cold, or you are buying for someone who does |
| Lower limit | Always colder than the comfort rating. The temperature at which a warm sleeper may still be comfortable. Brands use it on men's bags.[2] | You reliably sleep warm |
| Extreme (on some labels) | One maker that tests to the standard describes it as the lowest temperature at which the bag protects a standard adult from hypothermia, for about six uncomfortable hours.[11] | Never, for planning. It is an emergency figure, not a sleeping temperature |
REI advises choosing a bag rated a little lower than the coldest nights you expect, and notes that a temperature rating is not a guarantee of warmth for any bag.[3] Last verified November 2026.
Why the margin matters
The CDC says hypothermia is most likely at very cold temperatures but can occur even at cool temperatures, above 40°F, if a person becomes chilled from rain, sweat, or cold water. Its warning signs in adults include shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech, and drowsiness; in babies, bright red, cold skin and very low energy. If a person's temperature is below 95°F, the CDC says to get medical attention immediately.[6] Buy a bag with room to spare, and keep it dry.
The other half
The pad is half the warmth
A pad's warmth is its R-value: its resistance to heat flowing from your body into the ground. Higher is warmer. The standard test for it is ASTM F3340, which measures a pad on a heated plate in a lab so pads tested the same way can be compared.[4] Look for that test named on the box or listing.
The test covers air mattresses, self-inflating foam pads, and closed-cell foam mats. ASTM itself notes the result is a repeatable comparison value that may not capture everything about real use, such as edges and changes in posture.[4] Use it to compare pads, not to predict a temperature to the degree.
| Expected nighttime low | Pad R-value | Bag rating |
|---|---|---|
| Warm, about 50°F | Under 2 | 30°F or lower |
| Cool, about 32°F | 2 to 3.9 | 20°F or lower |
| Cold, about 20°F | 4 to 5.4 | 15°F or lower |
| Extreme, about 0°F | 5.5 or more | 0°F or lower |
Pairings from REI's sleep system table.[3] A floor inside a cold house is not the frozen ground of a winter campsite, but a bare floor still pulls heat out of your back, so even indoors a pad earns its place.
Closed-cell foam
A firm mat of foam that has no air to leak. Therm-a-Rest's Z Lite SOL is rated R 2.0, and the maker says laying it under another pad adds that 2.0 of warmth and protects the upper pad from punctures.[5] Bulky but nearly indestructible, and a good first pad for a household.
Self-inflating
Open-cell foam inside an airtight shell. Open the valve and the foam draws in air; top it off with a few breaths. More cushioned than a foam mat and warmer for its thickness, at the cost of more weight, more money, and a valve that can fail.
Air pads
The most comfortable and the smallest to pack. Warmth depends entirely on what is inside: an uninsulated air pad can be cold, while an insulated one like NEMO's Tensor All-Season is rated R 5.4.[12] Carry the repair kit, because a leak means a cold night.
The kinds of bags
Down or synthetic, mummy or rectangle
Two choices shape every bag: what fills it, and how closely it fits. Neither has one right answer. They depend on where the bag lives and how it will be used.
Down
REI describes down as lighter, more compressible, and more durable than synthetic, best in cold, dry conditions, and more expensive. Down loses insulating efficiency when wet, which is why most down bags now use water-repellent treated down. Its quality is rated by fill power: a higher number lofts more for its weight, and the priciest bags sit closer to 800 than 500.[3] Look for the RDS or TDS certification if responsibly sourced down matters to you.[3]
Synthetic
Polyester insulation costs less, keeps insulating when damp, dries quickly, and is non-allergenic, REI notes. There is no common fill-power scale for synthetics, so compare their ISO or EN ratings instead.[3] For a bag that waits in a closet or a car and comes out on a damp, cold night, synthetic is often the practical household choice.
Mummy
Slim, tapered, with a hood that cinches around your face. The warmest and lightest shape for its size, but snug: you roll over with the bag rather than inside it.[3]
Semi-rectangular
A middle ground, sometimes called a modified mummy or barrel shape, that trades a little warmth for room to move.[3]
Rectangular
The roomiest shape and the common one for camping and home use. The extra space makes it heavier and less efficient at holding body heat.[3] Many unzip flat into a blanket, which is handy on a couch during an outage.
A bag liner protects the bag from wear and dirt and adds a little warmth, which stretches its useful range.[3] For a household bag that gets lent around, it is an inexpensive way to keep the bag clean.
When the heat goes out
Sleeping warm in a cold house
During a winter power outage, the household that sleeps warm usually does it with layers, insulation underneath, and no flame anywhere near the beds. Most of that needs nothing you do not already own, and a good wool blanket or two covers much of the rest.
Start with what you have
Pick one smaller room and sleep there together; several people warm a small room better than a large one. Put something insulating under everyone: a foam pad, couch cushions, or folded blankets. Then layer comforters and sleeping bags on top. A dry hat and socks help, and dry is the key word, because the CDC notes that being wet from sweat or water raises the risk of hypothermia even in cool conditions.[6]
Who to check on
The CDC lists older adults without enough food, clothing, or heat, and babies sleeping in cold bedrooms, among the people most at risk of hypothermia.[6] In a long outage, they come first: the warmest room, the best bedding, and a check during the night. For a baby, the safe-sleep rules in the safety section still apply when the house is cold.
Wool blankets, the old standby
A wool blanket is one of the most useful things to have in a cold house. Spread over a sleeping bag or comforter, it adds another layer of trapped air on top. Folded double under you, it helps on a hard floor, though a foam pad does that job better for the money. REI notes a sleeping bag might not live up to its rating on a less-insulated pad,[3] so treat a folded blanket as a help, not a replacement.
Read the fiber label
Many wool camp blankets are blends. Arcturus's twin, for example, is 80 percent wool and 20 percent synthetic fiber, weighs about 4.5 pounds, and listed at $39.99 when we checked.[15] Pendleton's Yakima Camp twin is wool and cotton, weighs about 4.5 pounds, and listed at $228; the listing did not break out prices by size.[16] Price tells you more about the maker than about the warmth.
Check how it is cleaned
Care differs more than you might expect. Arcturus says to hand wash or machine wash its blanket separately in cold water on a delicate cycle, avoid top loaders with a center agitator, and line dry.[15] Pendleton lists its Yakima Camp blanket as dry clean.[16] A blanket you can wash at home is easier to keep in service after a week of use.
What we could not confirm
Some sellers, Arcturus among them, say wool keeps you warm even when wet and is naturally fire-retardant.[15] We could not find a government or standards source that measures either claim for blankets, so we do not count on them. Keep wool dry like any bedding, keep it at least 3 feet from heat sources,[9] and keep blankets of every kind out of a baby's sleep area.[10]
Keep the heat from becoming the danger
- The CDC says never to use generators, grills, or other gasoline-, propane-, or charcoal-burning devices inside your home, garage, or carport, or near doors, windows, or vents.[8]
- The CPSC says never to use fuel-burning portable heaters or lanterns while sleeping in enclosed areas such as tents, campers, and vehicles, and that people die every year from carbon monoxide poisoning from camping heaters, lanterns, or stoves used inside them.[7] A carbon monoxide alarm belongs in any home that burns fuel.
- The U.S. Fire Administration says to keep anything that can burn at least 3 feet from all heat sources, including space heaters, and to turn space heaters off when you leave the room or go to bed.[9] Sleeping bags, comforters, and pads all count as things that burn.
Our heating during outages guide covers safe ways to warm a room.
What fails and why
How a warm bag sleeps cold
Most cold nights are not a bad bag. They are a missing pad, a misread label, damp insulation, or a bag that spent a year crushed in its sack.
No pad, or the wrong pad
REI warns that a less-insulated pad in colder conditions can keep a bag from living up to its rating.[3] On a cold floor or the ground, the pad is the first thing to fix.
Reading the wrong number
A cold sleeper who buys by the lower limit, or by the rounded number in the name, will be cold at the temperature the label seems to promise. Read the comfort rating if you sleep cold.[3]
Stored crushed
REI says leaving a bag compressed in its stuff sack for long periods impairs its loft and insulation, and suggests a large mesh or cotton storage sack instead.[3] A bag kept for emergencies should be stored loose, not squeezed into its travel sack.
Damp insulation
Down loses insulating efficiency when wet.[3] Sweat counts: overheating in a bag, then cooling, is a slow way to get chilled. Vent the bag before you sweat, and dry it out in the daytime.
An adult bag for a child
The ISO standard does not cover children's bags,[1] so a child's warmth depends on the maker's own claim and on fit. A child swimming in a long adult bag has a lot of empty space to heat. A bag sized for children fits better.
A flame for comfort
A heater or lantern left burning in a tent, camper, car, or closed room while people sleep is how a cold night turns deadly. The CPSC also advises seeing a doctor if anyone develops cold or flu-like symptoms while camping, since those can be carbon monoxide poisoning.[7]
What a sleeping bag cannot do
It cannot make heat. It only slows the loss of the heat your body makes, so a person who is already chilled, wet, or showing signs of hypothermia needs to be warmed and may need medical care. The CDC says a body temperature below 95°F calls for medical attention immediately.[6]
It cannot guarantee a temperature. Even a lab rating is a comparison under set conditions, and REI notes a rating is not a guarantee of warmth for any bag.[3]
An adult or camping sleeping bag is not for babies. The NIH Safe to Sleep campaign advises keeping comforters, quilts, pillows, and blankets out of a baby's sleep area, keeping the baby's head and face uncovered, and dressing the baby in a wearable blanket instead.[10]
It cannot make an unsafe heat source safe. No bag protects against carbon monoxide or fire. Fuel-burning heaters, grills, generators, and lanterns stay out of the places people sleep.[7][8]
What to buy
Now that you know what to look for
Below are our full comparisons, honest prices for each kind of bag and pad, and the checks we hold every one against.
Affiliate disclosure: New World Survival earns a small commission on qualifying Amazon purchases at no cost to you. This helps us cover operating costs and keep building new content. We only recommend gear we would put in our own kit. Commission never decides a recommendation.
| Type | Typical price | What to know |
|---|---|---|
| Bedding you already own | Nothing | Comforters and blankets layered over a pad or cushions cover many nights at home. |
| Wool blanket | $39.99 for Arcturus's 80 percent wool twin[15] to $228 for Pendleton's wool and cotton Yakima Camp blanket, whose listing did not break out prices by size[16] | Layers over any bag or comforter. Check the fiber label and the care instructions. |
| Closed-cell foam pad | $49.95 for Therm-a-Rest's Z Lite SOL, R 2.0[5] | The best-value warmth upgrade. Layers under another pad later. |
| Rectangular synthetic camping bag | $59 to $119.95 for Coleman's rectangular bags at REI, rated 50°F down to 20°F[13] | Roomy and affordable. These listings show a single temperature rating, not ISO comfort and lower limit, so allow a margin. |
| Insulated air pad | $219.95 to $259.95 for NEMO's Tensor All-Season by size, R 5.4[12] | Warm and comfortable for its weight. Mostly worth it for camping; at home a foam pad does the job. |
| Down mummy bag rated into the teens | REI's Magma 15, with 850-fill down, ISO comfort 21°F and lower limit 9°F, listed at $399; it was discontinued, marked down to $278.93, and sold out in every size when we checked, so read it as a guide to what a premium down bag costs[14] | Light and compact for camping. More than most households need for a night at home. |
Prices from REI, Therm-a-Rest, Arcturus, and Pendleton listings checked November 8, 2026. Some items were sold out when we checked. Prices change often. These show what each type costs, not our picks.
Honest rating
- ISO or EN comfort and lower limit shown
- Comfort rating at or below your coldest night
- No reliance on the number in the name
Right pad
- An ASTM F3340 R-value listed
- R-value that suits your coldest night
- A foam pad for anyone on a floor
Right fit
- Length that suits the sleeper
- Room to move without much empty space
- Children's bags for children
Easy to keep
- A loose storage sack, not just a stuff sack
- Washable, or used with a liner
- A zipper that unzips flat as a blanket
Start small
For most households the first purchase is a foam pad for each person, because it makes every blanket and bag you own warmer on a cold floor. Add a roomy synthetic bag for anyone who will need one, and choose a lab-rated bag with a comfort rating at or below your coldest night if you also camp in the cold. A lighter, pricier down bag makes sense once you are carrying it on your back. For wind and rain on the road, our emergency shelter handbook covers blankets and bivvies.
After you buy
The first cold night, and the ones after
A bag in a closet is a start. These guides cover the rest of staying warm, at home and away.
Heating during outages
Safe ways to keep a room warm when the power is out, and the heat sources to keep out of the house.
Read the guideWinter storms
Power, heat, and frozen pipes: what to do before, during, and after a winter storm.
Read the guideHeating, fuel, and generator safety
Carbon monoxide, fire clearances, and fuel storage for the household that heats with something other than the furnace.
Read the guideCold and heat emergencies
Recognizing hypothermia and frostbite, and what to do while help is on the way.
Read the guideSleeping warm in a vehicle
Bags, pads, condensation, and carbon monoxide when the bed is the back of a car.
Read the guideCamping for beginners
The rest of the gear and skills for a first night outdoors, where a good sleep system makes the trip.
Read the guideAll comparisons
Every comparison, in one place
Each comparison we publish for sleeping bags and sleeping pads is listed here as it is finished.
Where this comes from
Sources
- International Organization for Standardization. "ISO 23537-1:2022, Requirements for sleeping bags, Part 1: Thermal, mass and dimensional requirements for sleeping bags designed for limit temperatures of -20°C and higher." Edition 2, March 2022. Accessed November 8, 2026. iso.org
- REI Co-op. "Understanding Sleeping Bag Temperature Ratings." Expert Advice. Accessed November 8, 2026. rei.com
- REI Co-op. "How to Choose Sleeping Bags for Backpacking." Expert Advice. Accessed November 8, 2026. rei.com
- ASTM International. "F3340-18, Standard Test Method for Thermal Resistance of Camping Mattresses Using a Guarded Hot Plate Apparatus." Superseded by F3340-22. Accessed November 8, 2026. store.astm.org
- Cascade Designs. "Therm-a-Rest Z Lite SOL Sleeping Pad." Product page. Accessed November 8, 2026. cascadedesigns.com
- Centers for Disease Control and Prevention. "Preventing Hypothermia." Winter Weather. Accessed November 8, 2026. cdc.gov
- U.S. Consumer Product Safety Commission. "Portable Heaters and Camping Equipment." Carbon Monoxide Information Center. Accessed November 8, 2026. cpsc.gov
- Centers for Disease Control and Prevention. "Avoiding Carbon Monoxide Poisoning." Natural Disasters public service announcement toolkit. Accessed November 8, 2026. cdc.gov
- U.S. Fire Administration. "Heating Fire Safety." Accessed November 8, 2026. usfa.fema.gov
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH. "Ways to Reduce the Risk of SIDS and Other Sleep-Related Causes of Infant Death." Safe to Sleep campaign. Accessed November 8, 2026. safetosleep.nichd.nih.gov
- Ferrino. "Sleeping Bag Temperatures: European Standard EN ISO 23537-1:2022." Maker's explanation of the rating definitions. Accessed November 8, 2026. ferrino.com
- REI Co-op. "NEMO Tensor All-Season Ultralight Insulated Sleeping Pad." Product listing with prices by size and R-value. Accessed November 9, 2026. rei.com
- REI Co-op. Coleman rectangular sleeping bags. Category listing with prices and temperature ratings. Accessed November 8, 2026. rei.com
- REI Co-op. "REI Co-op Magma 15 Sleeping Bag." Product listing with list and sale price, fill, and ISO tested ratings. Accessed November 8, 2026. rei.com
- Arcturus Gear. "Arcturus Military Wool Blanket." Product listing with fiber content, weight, price, and care instructions. Accessed November 8, 2026. arcturusgear.com
- Pendleton Woolen Mills. "Yakima Camp Blanket." Product listing with fiber content, sizes, weight, price, and care. Accessed November 8, 2026. pendleton-usa.com
- REI Co-op. "How to Choose a Sleeping Pad for Camping and Backpacking." Expert Advice. Accessed November 9, 2026. rei.com
Stay current
We re-check this guide every quarter as prices and products change. The Weekly Readiness Brief is a quiet way to hear when it updates.