The Best 20-Degree Backpacking Sleeping Bags, and Which 20F Ratings Mean Anything

“20 degree” is the most common sleeping bag rating sold, and it is also the least standardised number in backpacking. On this page, one maker's 20F is a comfort figure, another's is a survival limit with a comfort rating 25 degrees warmer, and a third publishes no test standard at all. All three are printed on the same shelf.

So every card below carries the maker's own rating wording, not a summary of it, and the page states which ones are tested. Then the standard ranking: grams saved against a mainstream reference bag, per dollar of list price. Full rules at our methodology page. For the whole bag catalog, see the budget sleeping bag ranking.

What a 20-degree rating actually means

None of the six bags here is ISO/EN tested. Paria states outright that it does not have EN/ISO testing, and Kelty publishes no test values on its product pages. That is not unusual at this price, but it does mean the only honest comparison is the loft and fill figures beside the rating. Our full guide to sleeping bag temperature ratings covers how the standard works and what to add for your own sleep.

How we picked

The gate: sold by its maker as a 20F-class bag, with a published weight and a published rating basis. The reference: the Kelty Cosmic Synthetic 20 at 1,276 g (2 lb 13.0 oz), itself a mainstream 20F bag, which makes it an unusually good baseline for this page: every gram saved here is a gram saved against a bag of the same claimed rating. Value is 35% of the score, weight 20%, warmth for the weight 25%, materials 10%, ease 10%.

The evidence side by side

The three down bags that lead the ranking.

The synthetic option and the two bags with survival-based ratings.

Only two bags here beat the mainstream reference on weight. That is the honest headline of this class: a 20F bag is a lot of insulation, and most of the cheap ones get there by adding fill rather than by using better fill.

Who each pick is for

1. Paria Thermodown 15: the best 20-degree bag overall

Rated 15F by Paria from measured loft, at 1,134 g (2 lb 8.0 oz). It saves 142 g (5.0 oz) vs the Kelty Cosmic Synthetic 20 against the reference for a value figure of Value 2.5/10, the best here. Paria publishes an FAQ page explaining that it has no EN/ISO testing and how it arrives at its numbers, which is more transparency than most brands at this price offer.

Buy it if you want the lightest 20F-class down bag that is not a cottage-brand price. Skip it if you need a tested rating on paper.

2. Kelty Cosmic Down 20: the big-brand pick

550-fill down, a full draft collar, recycled shell and lining, at 1,106 g (2 lb 7.0 oz). The lowest fill power here, which is exactly why it packs larger than the Paria for a similar weight. What it buys you is a brand with US shops, a warranty process and stock you can actually find.

Buy it if availability and support matter. Skip it if pack volume is your constraint; 550 fill takes roughly twice the space of 800 fill for the same warmth.

3. Kelty Women's Cosmic Down 20: the women's cut

The same bag with a women's shape, 840 g of 550-fill down and both a 0F full draft collar and a 20F upper collar, at 1,420 g (3 lb 2.1 oz). That is 314 g more than the unisex version for the same stated rating, which is the extra insulation doing its job. Against our reference it saves nothing, and the score shows it.

Buy it if you sleep cold and want a bag cut for it. Skip it if grams are the priority; see the women's bag page for the lighter options.

4. Kelty Women's Cosmic Synthetic 20: the wet-weather budget pick

1.37 kg of recycled CirroLoft synthetic fill, the lowest list price on this page, and the only bag here that keeps loft when it gets soaked. At 1,790 g (3 lb 15.1 oz) it is the heaviest bag we have listed and it packs to 9.5 x 18 in, which is a large share of a 50 L pack.

Buy it if your trips are wet and your budget is hard. Skip it if you carry a small pack; this bag will define how you pack it.

5. Hyke & Byke Eolus 15: the lightest 800-fill

800-fill goose down with differential fill, at 1,152 g (2 lb 8.6 oz). Read the rating chart on its own card before you buy: Hyke & Byke publishes comfort 50F, comfort limit 30F and survival limit 15F for this bag. As a 30F bag it is competitive; as a 20F bag it is not what the name implies.

Buy it if you want a light 30F-class down bag and read the chart. Skip it if you are shopping for real 20F warmth.

6. Teton Trailhead 20: the budget bag with the loosest rating

The cheapest bag on this page by a wide margin, at 1,579 g (3 lb 7.7 oz). Teton's own page lists 20F as a survival rating, puts comfort at 45-50F and suggests adding 20-30 degrees to its numbers. Treated as a 45F summer bag it is fine value; treated as a 20F bag it is a cold night.

Buy it if you camp in summer and want a cheap first bag. Skip it if the temperature on the label is the reason you are buying it.

Should you buy a quilt instead?

The catch is that a quilt needs a pad with enough R-value to replace the missing back insulation, plus a draught-free strap system, plus a hat. For a 20F night that is real: see quilt vs sleeping bag and R-value explained before you switch.

What missed the cut

20F quilts. The Therm-a-Rest Vesper 20 and Enlightened Equipment Revelation 20 are both 20F-class and both lighter than everything here, but they are quilts, not bags. They are ranked on the quilt page.

The Hyke & Byke Eolus 30. A 30F bag by the same rating chart logic, lighter again. If you decided after reading this page that you actually want a summer bag, it is on the main bag ranking.

The Kelty Cosmic Synthetic 20 is the reference this page is scored against, at 1,276 g (2 lb 13.0 oz). If you own one already, the only bags here that would save you weight are the Paria and the Kelty Cosmic Down 20.

How to choose a 20-degree sleeping bag

1. Find out which number you are reading. Comfort, lower limit and survival are three different temperatures. Two bags on this page label a survival number as the rating.
2. Check fill power, not just fill weight. 550 fill and 800 fill can produce the same warmth; the 800 will weigh and pack about half as much and cost more.
3. Decide down or synthetic first. Down is lighter and packs smaller; synthetic keeps working wet and costs less. See down vs synthetic.
4. Match the pad to the bag. A 20F bag on a 1.3 R-value pad is a cold night regardless of the bag. Aim for 4 or better.
5. Check the length you need. Both Kelty bags fit to 5 ft 8 in; taller sleepers need a Long, which adds weight and cost.
6. Add a margin for how you sleep. If you sleep cold, buy the rating below the temperature you expect, not at it.

Mistakes to avoid

• Buying on the number on the stuff sack. Teton's own page suggests adding 20-30 degrees to its rating. That is not a criticism of Teton; it is a warning about the category.
• Pairing a 20F bag with a summer pad. The ground takes the heat, not the air.
• Assuming a women's bag is just a smaller bag. Kelty's women's Cosmic Down 20 carries 840 g of fill and weighs 314 g more than the unisex version at the same stated rating.
• Ignoring pack volume. A 550-fill bag and an 800-fill bag can weigh the same and take very different amounts of space.