Companion Articles:

patagonia micropuff pullover - field shot
The Patagonia Micro Puff Pullover stood out among the jackets and pullovers tested. Here, our Product Review Director Alan Dixon is obviously enjoying field testing the Micro Puff in the Yellowstone backcountry.


Synthetic insulation garments fill a unique niche. They outperform fleece as an insulating garment in every category but breathability and water absorption. They are warmer for their weight, windproof, more water resistant, and more compressible. In wet conditions, synthetic fill garments maintain their warmth and loft better than down garments which lose loft and are slow to dry and regain their loft. You can actually wear a synthetic garment in rain or wet snow or use it to dry out damp clothing. Despite these advantages, relatively few manufacturers have focused on innovative synthetic fill lightweight garments; especially when compared with the volume of garments made from fleece or its derivatives. In this overview and companion gear guide we take a closer look at 15 lightweight synthetic fill garments; of these, 9 are reviewed. Under most conditions these garments are excellent and versatile performers and can be a key part of lightweight clothing and sleep systems for three-season outings.

The garments in our sample have a range of performance objectives. Some manufacturers have focused on weight reduction, others on maximum warmth, still others on versatility and comfort. Three key features play a primary role in influencing the performance and suitability of a garment in any given situation: fill type and weight, garment style (full zip jacket, pullover, or vest), and shell material. Of course workmanship, quality and other features will also play an important role in performance and value. At 8.0 ounces (men’s medium) the Montbell U.L. Thermawrap jacket is more than 4 ounces lighter than the next lightest full zip jacket in our sample. Clearly Montbell has focused on weight reduction, but has traded some insulation and warmth to do so. At 12.0 ounces (men’s large) the Integral Designs Logan Vest has sacrificed some weight savings in order to provide more core insulation than any other garment in our overview. And at 11.0 and 12.7 ounces respectively (men’s medium), the Patagonia Micro Puff Pullover and the Moonstone Cirrus Ultralight provide a nice balance of lightweight insulation and other features. The Montane Solo Jacket is notable for providing a full zip jacket and a non-insulated hood while still coming in at 15.9 ounces (men’s medium).

Overall, our reviews and ratings reflect our choices of high performing garments. None of the garments faired poorly. The Patagonia Micro Puff Pullover stands out among the jackets and pullovers, with excellent loft to weight ratio, low overall weight, and high performing Polarguard Delta insulation. For most three or even four-season outings, it would be hard to find a better performing garment for the weight. And it is quite a value to boot. For the gram shavers in the crowd (we know you’re out there) the Montbell U.L. Thermawrap jacket is a great option. If you don’t need quite the warmth or storm protection of the Micro Puff, the U.L. Thermawrap is 3 ounces lighter, has a full zip for added temperature control, and is still windproof and quite warm. Those desiring more features such as hand warmer pockets would do well to look at some of the other garments in our sample. Finally, the Mountain Equipment Co-op Northern Lite Pullover and Vest should be singled out as stellar values. At only $79 and $68 Canadian respectively (about $60 and $52 US) they have performance comparable to many garments we reviewed at half the price for the pullover and nearly so for the vest.

Synthetic Insulation Overview

integral designs logan vest - field shot
Don Wilson, Clothing Systems Section Editor, wearing the Integral Designs Logan Vest in the Savage River Valley, Denali National Park, Alaska. The Logan Vest had the highest loft of any garment we tested.

Synthetic fill insulation, as opposed to a synthetic insulating fabric (such as fleece) is what defines this category. There are three commonly used insulation types in these jackets; Primaloft, Polarguard, and Thermolite. Additionally, Montbell uses a proprietary synthetic fill insulation called Exceloft. Of the 15 garments featured in our gear guide, seven use variants of Primaloft insulation, four use Polarguard, two use Thermolite and the two from Montbell use Exceloft. Insulation weights also vary from the lightweight 1.8 oz/yd2 in several garments to the 5 oz/yd2 in the Integral Designs Logan Vest.

Two variants of Primaloft insulation are used within our sample; Primaloft One (also shown as PL1 by some manufacturers in the Gear Guide) and Primaloft Sport (previously called PL2). Primaloft One is the premier insulation from Primaloft. All Primaloft insulations are cut staple, non-continuous filament fibers. Primaloft uses a patented ultrafine microfiber blend which is treated in a proprietary process and combined with an insulating core. According to the manufacturer’s specifications, Primaloft One has the same thermal performance when wet or dry (0.84 clo/oz/yd2). Primaloft Sport is less efficient than Primaloft One, and loses some performance when wet (0.73 clo/oz/yd2 when dry and 0.65 clo/oz/yd2 when wet) according to manufacturer’s specifications (Editor’s Note: to learn more about the “clo” unit of measure read Alan Dixon and Ryan Jordan’s article, Commentary on Sleeping Bag Rating Specifications (2004) (M)).

The Patagonia Micro Puff Pullover is the only garment using Polarguard insulation in our review sample. The Micro Puff uses 2.6 oz/yd2 Polarguard Delta. All Polarguard insulations are continuous filament insulations, which, according to the manufacturer, make them more durable and strong and less likely to form clumps or mattes than cut staple insulation such as Primaloft. Continuous filaments also help to maintain insulation when wet. On the other hand, Polarguard will absorb more water than Primaloft insulation of the same weight. Previous experiments by Backpacking Light confirm these claims. In our tests, Polarguard 3D did absorb more water than Primaloft One fill of the same weight, but the Polarguard 3D had superior performance in maintaining insulation when wet. Polarguard Delta, as used in the Patagonia Micro Puff Pullover, is the latest and most efficient insulation offered by Polarguard.

Thermolite is a non-continuous fill insulation manufactured by Dupont and is used in the Moonstone Cirrus Ultralight and Patagonia Puffball Vest. We have not performed comparison tests using Thermolite insulation. It is an economical insulation that loses approximately 25% of its insulation performance when wet, based on manufacturer’s specifications.

Montbell Exceloft is a non-continuous (cut staple) insulation that uses multiple diameters of polyester threads to provide structure and insulation.

Shell Material Overview

All of the garments in our sample use a water resistant polyester or nylon shell. These shells typically provide excellent wind protection in addition to moderate protection from light rain or showers. These characteristics make the group as a whole quite versatile; they can serve as wind shell, insulating garment and moderate moisture protection. The tight weave shells in these garments are less breathable than fleece, but more breathable than waterproof breathable fabrics. These shells are breathable enough for use in bivies under most conditions, but you may get overheated in high aerobic-output activities. Features that can improve breathability and temperature control, such as more-breathable fabrics under the arms (or vest style) and full zippers, can help to alleviate this potential drawback.

Several garments in our sample group use Pertex Quantum shells. Pertex Quantum is a very lightweight (0.9 oz/yd2), water resistant and breathable fabric that has found wide use recently in lightweight jackets, sleeping bags, bivy sacks and other products. Very light and highly breathable, Pertex Quantum does not provide the durability of heavier shell materials. In our review sample, the GoLite Buzz and Montane Solo use Pertex Quantum shells, as does the Berghaus Infinity Lite listed in the Gear Guide.

Garment Style and Other Features

Garment style plays a significant role in the performance of these garments. Full zip jackets, pullovers, and vests each have pros and cons when it comes to performance, weight, and temperature control. Some manufacturers have clearly focused on providing performance per weight – using the lightest fabrics and zippers, and reducing features. Montbell’s line of U.L. Thermawrap garments is the most extreme example of this within our sample. Integral Designs Logan Vest, by virtue of its design as a vest and its heavy 5 oz/yd2 insulation, has the best core insulation of any garment in our sample – but weighs 12 ounces for the men’s large. Usability features such as a durable, heavy zipper and hand warmer pockets make it clear that weight has been traded for additional durability and comfort. Still another example of trading features and performance is Patagonia’s Micro Puff Pullover and the new Moonstone Cirrus Ultralight. Both of these garments provide full sleeves, weigh less than 13 ounces and have mid range thickness insulation.

Ratings Chart for Lightweight Synthetic Fill Garments reviewed by Backpacking Light

Ratings are from 1 – worst, to 5 – best

Manufacturer/Model/Style Field Warmth Storm Resistance* Loft to Weight Performance** Usability Value Average Score
GoLite Buzz Jacket 4.0 4.0 1.0 4.5 3.5 3.4
Montane Solo Jacket 4.0 4.0 1.0 5.0 3.5 3.5
Montbell U.L. Thermawrap Jacket 3.5 3.5 3.1 4.5 4.5 3.8
Moonstone Cirrus Ultralight Jacket 4.0 4.0 2.4 4.5 4.0 3.8
Mountain Equipment Co-op Northern Lite Pullover 4.0 4.0 2.6 4.0 5.0 3.9
Patagonia Micro Puff Pullover 5.0 4.0 5.0 4.0 4.5 4.5
Integral Designs Logan Vest 5.0 4.5 4.3 4.0 4.0 4.4
Montbell UL Thermawrap Vest 3.5 3.5 3.0 4.0 4.5 3.7
Mountain Equipment Co-op Northern Lite Vest 4.0 4.0 2.7 4.0 5.0 3.9

* The Storm Resistance of the vests is rated compared to other vests reviewed.

** Loft to Weight Performance is a normalized score with the lowest loft to weight performance receiving a 1.0, and the highest a 5.0. Loft to Weight performance scores for vests were adjusted by a factor of 0.72 to keep them consistent with jackets. This factor was derived from the two garments which were tested in both jacket and vest form.

A caution: the average rating scores are a guide. Choose the garment that best meets your performance and budget needs.

In Brief Specifications for Lightweight Synthetic Fill Garments reviewed by Backpacking Light

Manufacturer/Model/Style Fill Type Shell Fabric Weight
oz (g)
In (cm)
Loft/ Weight (in/oz x 100) MSRP
GoLite Buzz Jacket (size Large) Primaloft One (1.8 oz/yd2) Pertex Quantum w/DWR 15.9 (451) 0.3 (0.8) 1.89 $149
Montane Solo Jacket Primaloft One (1.8 oz/yd2) Pertex Quantum w/Shield 15.9 (451) 0.3 (0.8) 1.89 $145
Montbell UL Thermawrap Jacket Exceloft (1.8 oz/yd2) Ballistic Airtight Nylon 8.0 (360) 0.3 (0.8) 3.75 $129
Moonstone Cirrus Ultralight Jacket Thermolite (2.4 oz/yd2) High Tenacity Ripstop Nylon 12.7 (343) 0.4 (1.0) 3.15 $140
Mountain Equipment Co-op Northern Lite Pullover Primaloft One (1.8 oz/yd2) Microfiber polyester 12.1 (343) 0.4 (1.0) 3.31 $60 ($79 Canadian)
Patagonia Micro Puff Pullover Polarguard Delta (2.6 oz/yd2) Microdenier ripstop w/ DWR 11.0 (312) 0.6 (1.5) 5.45 $145
Integral Designs Logan Vest (size Large) Primaloft Sport (5.0 oz/yd2) Pertex P565 w/DWR 12.0 (340) 0.8 (2.0) 6.67 (vest) $100
Montbell UL Thermawrap Vest (size Large) Exceloft (1.8 oz/yd2) Ballistic Airtight Nylon 5.9 (167) 0.3 (0.8) 5.08 (vest) $99
Mountain Equipment Co-op Northern Lite Vest Primaloft One (1.8 oz/yd2) Microfiber polyester 8.5 (241) 0.4 (1.0) 4.71 (vest) $52 ($68 Canadian)

Note: Weights and lofts are as measured by Backpacking Light for size Medium unless other wise noted. Loft measurements are for a single layer of loft in the torso.

GEAR GUIDES: Lightweight Synthetic Fill Jackets/Pullovers and Vests

Gear Guide Selection Criteria:

  • Garments using synthetic fill insulation
  • Weight less than 18 ounces
  • Jacket, vest, or pullover style

REVIEW CRITERIA: Lightweight Synthetic High Loft Insulating Jackets/Pullovers and Vests


Describes the insulation used, and the warmth of the garment when fully zipped up. Evaluates how any other features (collar, hood) contribute to warmth retention. May include tests in both stationary and active use, or as part of a sleeping system.

Storm resistance

Describes the shell fabric and any salient storm resistance features. Includes a description of conditions in which the garment was tested and an evaluation of storm resistance. Water resistance, water absorption and wind resistance are evaluated. May include an evaluation of jacket performance when wet, and drying time in field conditions. Vests are rated as compared to other vests.


A general description and evaluation of features and qualities that enhance usability. This may include fit, articulation, durability, torso coverage, pockets, hood, stuff sacks, adjustability, comfort and other unique features of the garment.


This is our most subjective rating. It takes into account all of the above criteria and the garment’s price and quality. Warmth, weight and loft/weight ratio are primary factors.

INDEX OF REVIEWS: Lightweight Synthetic High Loft Insulating Jackets/Pullovers and Vests

Manufacturer – Model

M GoLite Buzz Jacket

M Montane Solo Jacket

M Montbell UL Thermawrap Jacket

Moonstone Cirrus Ultralight Jacket

M Mountain Equipment Co-op Northern Lite Pullover

M Patagonia Micro Puff Pullover

M Integral Designs Logan Vest

Montbell UL Thermawrap Vest

M Mountain Equipment Co-op Northern Lite Vest