Insulated jacket buying guide: How to choose a winter jacket

Buying a high quality, insulated jacket is just about the most significant investment you can make when it comes to performance outerwear. As such, it’s important you get it right. The correct insulated jacket will have your back when the temperature drops, keeping you comfortable enough to enjoy your chosen pursuits unaffected by the elements. This following guide will tell you everything you need to know in order to ensure that the next insulated jacket you buy is the right one for you.

How should an insulated jacket fit?

When assessing whether the fit of an insulated jacket is correct or not, it’s important to remember how an insulated jacket works - by trapping heat generated by the body and preventing not only the escape of body heat but the ingress of cold wind, rain and snow etc.

The fit of an insulated jacket should:

  1. Provide sufficient coverage of your extremities with sleeve cuffs falling just beyond the wrist, the hem of the jacket sitting just below the waist, and a neckline high enough to offer some protection for the face.

  2. Not be too tight so as to be unbreathable and impractical for functional use.

  3. Not be too loose so as to allow heat to escape and elements to ingress.

If you’re going to be wearing an insulated jacket for technical pursuits requiring a harness or helmet, you should also consider how the jacket will sit on/around the harness, if the pockets will remain accessible, and whether a helmet will fit under or over a hood.

Choosing a winter jacket: What to consider

Type of insulation

When thinking about types of insulation you will want to consider the type of environment/climate you’re purchasing the insulated jacket for – the key distinction being are you likely to get wet or not?

If you’re buying the insulated jacket for cold and wet/damp conditions then you will be better served by choosing a jacket with synthetic insulation. Synthetic insulation retains heat better when wet and will dry more quickly than down if it gets damp.

On the other hand, if you’re less concerned by wet conditions then down offers the best weight to warmth ratio and generally packs down more easily when not being worn.

For these and other considerations check out our detailed guide below on the different types of insulation available.

Discover Ithax, our synthetic insulation jacket

Type and size of baffle

The way in which an insulated jacket is stitched can have differing effects on performance also. The stitched compartments on the jacket that contain the down fill/synthetic insulation are called “baffles”. These baffles come in different structures:

Stitch Through

Stitch Through baffles keep insulation distributed evenly, but as they are stitched right the way through from the outside of the jacket to the inside, this can lead to some heat loss through the seams.


Stitch Through Baffles

Box Wall

On the other hand, Box Wall baffles are not stitched right the way through. They leave a gap between the outside and the inside of the jacket, in order to minimise heat loss. The structure of box wall baffles is designed to encourage insulation to expand to a maximum level of loft in order to trap as much heat as possible.

The width of the baffles on a jacket will also make a difference. Wider baffles are able to store more insulation but will not pack down as well. Otherwise, more narrow baffles will sacrifice some insulation for improved packability and will offer greater space to layer under a hard shell.

Pursuit or activity

The type of activity you’re buying the jacket for may have a bearing on what type of insulated jacket you choose. This ties into the discussion around types of insulation we referenced earlier, remembering that synthetic insulation is generally breathable and fast drying where down tends to be warmer.

For dynamic pursuits or periods of high activity, whether that be climbing or winter hiking, you’ll likely want to go for the improved breathability of synthetic insulation.

Otherwise, for more stationary tasks, where you won’t be generating quite as much body heat, the greater insulating qualities of down would be better placed to keep you protected from the cold.

It’s also worth thinking about packability. For multi day expeditions where carrying less weight is key, you might want to consider the lighter more packable benefits of down compared with the typically more bulky nature of synthetic insulation.

Shop Down Insulation Jackets
Shop Synthetic Insulation Jackets

Hood or no hood

The choice between a hooded and a non-hooded insulated jacket is a fairly straightforward balancing act depending on whether you want the maximum coverage provided by a hood (but at an additional weight) or whether you’d rather go without (and save on weight), improving packability. It’s worth bearing in mind that in extreme cold you can lose up to 45% of your body temperature through your head - so don’t scrimp on weight if you’re heading for sub-zero.

Pocket features

Most insulated jackets will come with external hand warmer pockets. Some may offer zipped chest pockets and/or internal mesh pockets for stowage of items closer to the body’s core. Your storage needs will depend on the task at hand, the only balancing act being the greater the amount of items required for storage, the added weight burden on the jacket and your level of activity.

Waterproof construction

It’s uncommon to find waterproof insulated jackets. The reason being there is often a balancing act to be had between waterproofing and breathability. Generally speaking the more waterproof a garment is, the less breathable it is (and vice versa). With an insulated jacket you want breathability, as this will prevent overheating and sweat buildup – sweat buildup will cause your body temperature to drop in cold conditions.

That being said, in order to protect the insulating qualities of down which is impaired when wet, most insulated jackets will be treated with a durable water repellent or “DWR”. This helps provide a level of shower proofing in order to protect the insulation for a short period of time.



ThruDark’s water-proof and water-resistant jackets make for a flexible armoury that can be deployed in a range of wet conditions and scenarios.

Weight and compressibility

Another issue we touched on earlier is the subject of weight and packability. Traditionally, down has a higher weight to warmth ratio than synthetic insulation and compresses and packs down more easily. Owing to its structure, synthetic insulation tends to be bulkier.

This means that your insulation needs may differ by pursuit, with down preferred for multi-day expeditions where you need something packable whilst synthetic may be preferable for day trips where you’re unlikely to be stowing the jacket away for prolonged periods of time.

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