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Patagonia Lightweight Sleeping Bag Review

A feather-light mummy sleeping bag that hardly supplies enough warmth to be useful
patagonia lightweight sleeping bag ultralight sleeping bag review
Credit: Patagonia
Price:  $200 List
Manufacturer:   Patagonia
By Jack Cramer ⋅ Review Editor  ⋅  May 5, 2021
  • Warmth - 30% 3.0
  • Weight - 25% 10.0
  • Comfort - 20% 4.0
  • Versatility - 15% 6.0
  • Features - 10% 4.0

Our Verdict

When we saw the specs for the Patagonia Lightweight Sleeping Bag our hopes soared. Just 9.8 oz for an affordable "sleeping bag"?!? When we laid our hands on one, however, our hopes were dashed. Its meager quantity of 40-gram Primaloft Gold insulation is simply not enough to supply meaningful warmth. Sure, it's light and it packs down incredibly small, but it's difficult to imagine a situation where this model could function as a useful standalone sleeping bag. It does make sense as a liner bag to boost the temperature rating of another sleeping bag on a cold night. But in temperatures hot enough for you to possibly desire this bag's tiny level of warmth, we think you would probably be better off with no sleeping bag at all.
Reasonable price
Rock-bottom weight
Simple design
Disappointing warmth
Cramped dimensions
Limited versatility

Our Analysis and Test Results

Performance Comparison

patagonia lightweight sleeping bag ultralight sleeping bag review - the ideal situation for the patagonia lightweight sleeping bag is a...
The ideal situation for the Patagonia Lightweight Sleeping Bag is a warm summer night when you hardly even need a sleeping bag.
Credit: Jack Cramer


Patagonia chooses not to assign their Lightweight Sleeping Bag a temperature rating. If we had to give it one, we would estimate it at 60F. This lack of warmth is a consequence of this bag only featuring a thin layer of Primaloft Gold for insulation. It's simply too thin to contain much body heat. This model could serve as a useful liner bag to boost the temperature of another sleeping bag, but in the hot summer temperatures where it might be acceptable on its own, we think you're better off with a puffy jacket and insulating pants, or maybe an emergency bivy.

patagonia lightweight sleeping bag ultralight sleeping bag review - it's easy to see that the patagonia lightweight sleeping bag's...
It's easy to see that the Patagonia Lightweight Sleeping Bag's Primaloft Gold insulation (left) doesn't offer nearly as much loft as premium, 950 fill power goose down (right).
Credit: Jack Cramer


When we laid a size Regular on our scale, we weren't sure if the reading was right. We had never seen a sleeping bag weigh less than 10 ounces. This model checked in just under at an insane 9.8 ounces. This is certainly impressive but we would like to caution this product doesn't provide anywhere close to the warmth of an ordinary sleeping bag. In fact, we think its overall warmth-to-weight ratio is worse than an average sleeping bag.

If you're still tempted though, we can report that its included stuff sack is also very light at 0.4 oz. We think this sack is sized nicely for compressing the bag. However, we would not use the secondary drawcord that expands the sack and allows it to be used as a storage sack. Instead, hang the bag up while storing it and you will preserve what little loft it has.

patagonia lightweight sleeping bag ultralight sleeping bag review - weight is a critical aspect of any outdoor gear, but it's...
Weight is a critical aspect of any outdoor gear, but it's particularly important to ultralight travelers.
Credit: Jack Cramer


This zipperless mummy bag is constructed with a subtle taper from the shoulder to the foot of the bag. The dimensions are predictably narrow, especially at the footbox. Although our testers liked the feel of its 10-denier nylon fabric, they still scored its overall comfort at well below average. This bag is so minimalist that it only seems suitable for single-night missions, where the fatigue level rises so high that you could sleep in practically anything.

patagonia lightweight sleeping bag ultralight sleeping bag review - the lightweight sleeping bag from patagonia packs down to roughly...
The Lightweight Sleeping Bag from Patagonia packs down to roughly the size of a one-liter Nalgene bottle.
Credit: Jack Cramer


One advantage that this bag has over many other ultralight sleeping bags is the ability to maintain its warmth even if it gets wet. That's a consequence of its synthetic Primaloft Gold which won't clump like down feathers if the rain starts to fall. The low-profile design of this model also means that it can function well as a sleeping bag liner to boost the warmth of another bag in cold conditions. In fact, we think being a liner bag is probably this model's ideal use.

In other ways, the Patagonia Lightweight Sleeping Bag is less versatile. The zipperless design means that it's difficult to vent excess heat or share this bag between two people. We think the usable temperature range is also disappointingly small, extending from temps so high that you don't need a sleeping bag, down to roughly 60F.

patagonia lightweight sleeping bag ultralight sleeping bag review - this patagonia bag is borderline acceptable in summer conditions...
This Patagonia bag is borderline acceptable in summer conditions, but absolutely miserable if the mercury drops.
Credit: Jack Cramer


This extremely lightweight bag is understandably light on features. Although it might appear to have vertical baffles, the stitches do not continue to the inside of the bag. Instead, the synthetic matting is contained inside a baffle-less space between the shell and lining fabric. There is a small band of elastic at the collar to help seal the bag close and trap heat inside. In our tests, this elastic seemed to be inadequate--we wish there were a drawcord to close the bag more securely.

patagonia lightweight sleeping bag ultralight sleeping bag review - a thin strip of blue elastic attempts to seal in heat at the collar...
A thin strip of blue elastic attempts to seal in heat at the collar. We think a slim drawcord might be much more effective.
Credit: Jack Cramer


Compared to many of the premium ultralight options, the Patagonia Lightweight model is available at a bargain price. Unfortunately, due to its meager warmth, we do not believe it provides a decent value. There are several other synthetic models near and below this price that offer better warmth with a similar weight. And if you consider this bag's most likely use as a liner bag inside another sleeping bag, the price seems a lot steeper.


It can be hard to figure out when ultralight principles get taken too far, but the Patagonia Lightweight Sleeping Bag seems to be a clear example. At just 9.8 oz for a "sleeping bag", it is an awfully tempting bargain. However, its warmth is so minimal that we struggle to classify it as a sleeping bag at all. Instead, we think this model's best use is as a liner bag for other sleeping bags or as a survival sack in an emergency.

Jack Cramer
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