Therm-a-Rest Questar HD Sleeping Bag Review

© Richard Prideaux

Therm-a-Rest: Don't they do sleeping mats? Well, yes they do. But it turns out - and this was news to me - they also make some rather good sleeping bags. Making good use of Nikwax Hydrophobic Down, the Questar HD has proven itself to be an excellent 3-season down bag for camping in the often-damp British climate.

An excellent choice for damp UK conditions  © Richard Prideaux
An excellent choice for damp UK conditions
© Richard Prideaux

Down versus synthetic

For several years now, my favoured fill for sleeping bags has been synthetic. The synthetic products on offer have improved in performance whilst simultaneously reducing in weight and bulk. For damp, British adventures all year round down bags have often let me down, particularly for the second and third nights. However, I'm prepared to change my mind when offered something better.

The Therm-A-Rest Questar HD deals with that issue straight away with 610g (size L) of 650-fill Nikwax Hydrophobic down. So far I have used this bag inside a bivvy bag, on a damp multi-day wild camp in Snowdonia and on its own under a tarp in various forests, and not once have I noticed the familiar clumpiness that down bags with a traditional non-hydrophobic fill always get when exposed to moisture. Nikwax claim that this down absorbs 90% less water and dries three times faster than equivalent untreated down, and that it also maintains its warmth-trapping loft a lot more effectively; though it's hard to quantify these claims in real world use, the general impression is that this hydrophobic stuff really works in challenging damp conditions. Care is also not much of a worry, with claims that it will survive five washes, and that it can be re-treated with Nikwax products.

For more on that down, here's a promo video from Nikwax:

Unusual feature

An obvious feature is the SynergyLink strap system. These two straps attach via toggles to loops underneath, and have enough stretch to wrap around most sleeping mats or pads, with the aim of keeping the mat and bag together when you turn over. This is a neat solution to a problem I've had before - mats slipping away or the sleeping bag sliding off – but hitherto I have not really given it much thought. I admit that I was dubious of how well the system would work but in the event I was mildly surprised. Normally when I roll to my side the sleeping bag rolls with me, but this feels more like a duvet in the way that it stays in place, and so far I've remained attached to the pad all night every night.

The 'Synergy Link' strap system holds the bag onto a map  © Richard Prideaux
The 'Synergy Link' strap system holds the bag onto a map
© Richard Prideaux


The bag is rated for comfort at 0C, which feels realistic to me, and has a rather more optimistic 'transition' limit of -6C. To help with warmth without adding much weight, the down fill is backed up by 'ThermaCapture technology'. This is a lightweight coating on the inner that helps keep heat in and allows the bag to warm up more quickly. In addition the down fill is zoned, with more on top where you need it and less underneath, where you'll already have insulation from your camping mat, and the down will be compressed in any case. As a user it's difficult to assess how far all this has a bearing on performance, but the temperature rating for the bag certainly feels about right. On a mountain bivvy I felt cold spots where the insulation was compressed, but the ambient temperature there was hovering just below freezing with a light breeze - relatively marginal conditions for comfort in this bag, in other words.

Nicely shaped hood for a snug fit around the head  © Richard Prideaux
Nicely shaped hood for a snug fit around the head
© Richard Prideaux

In Use

My review sample was the Long version (198cm), which proved just about right for my 6'2" frame, and I didn't really feel constricted inside (think Brian Blessed more than Kilian Jornet when you picture me). The hood and neck baffle sit just where you need them to without inducing claustrophobia, and an external zip pocket on the right shoulder gives you somewhere to stash a headtorch (or earplugs in case of noisy tent companions).

A manageable pack size in its stuff sack  © Richard Prideaux
A manageable pack size in its stuff sack
© Richard Prideaux

Small zip pocket for bits and bobs  © Richard Prideaux
Small zip pocket for bits and bobs
© Richard Prideaux

A separate wall of insulation runs between the leg and foot area, creating a toe box that's supposed to help your feet warm up fast. I didn't find that this worked that well for me, particularly as I tend to sleep on my side and the SynergyLink system keeps the bag in the same orientation so my feet end up out of that box.

The build quality seems solid enough, and the zips (left side entry) and drawcords all run freely without snags. The fabric does seem to pick up dirt quite easily, but on the upside also seems quite resilient to scrapes and scuffs. I have used it without a bivvy bag on the forest floor several times and with nothing unhappy to report.

The Therm-A-Rest Questar HD comes with the familiar pairing of a compressible stuff sack and a roomy netting bag for storage at home. When packed down it is around 23x36cm – a little more than other similar bags on the market perhaps, but not too bad; and the 1.1kg weight (Long version) is just about acceptable for a bag of this warmth too. I suspect that the straps and the hydrophobic down have both added weight that has pushed it just over what you might expect from a down bag in this category; in the case of the down in particular though, you may well feel that it's a tradeoff worth making for its increased damp weather performance.

Camping under a tarp with no bivvy bag, and not regretting it  © Richard Prideaux
Camping under a tarp with no bivvy bag, and not regretting it
© Richard Prideaux

Final thoughts

The Questar HD is a 3-season down bag that has a couple of interesting features – namely, hydrophobic down and straps that keep you and your mat together. If you want a lighter bag or smaller packed size it might not be the best for you, but there is a lot to like here, and certainly no major grumbles as regards general design. The hydrophobic down fill and the shape both suit me, and I have to say that it has drawn me back towards down for British outdoor adventures. If it can survive two consecutive nights of bivvying then it should be fine for most other things – as long as you stay around or above 0 degrees. For the quality of down and general workmanship on offer, the RRP of £200 seems more than reasonable - and if you shop around you may find it cheaper than that too.

Therm-a-Rest say:

Three season comfort in a feature-packed hydrophobic down bag. We've loaded this bag with the comfort-enhancing hallmarks Therm-a-Rest bags are known for, such as our SynergyLink Connectors, which integrate the bag with a mattress, and our ThermaCapture Seams that trap your radiant body heat. Stuffed with water-resistant 650 fill Nikwax Hydrophobic Down, and sporting integrated Quilt and Blanket Loops for sleep system customization, the three-season Questar is ready for your next backcountry adventure.

  • Price: £200 - £225 depending on size
  • Sizes: Small 156-168cm; Regular 170-183cm; Long 185-198cm
  • Weights: Small 946g; Regular 1062g; Long: 1166g
  • Fill: 650 Fill Nikwax Hydrophobic Down
  • Fill weight: Small 470g; Regular 540g; Long 610g
  • Nikwax Hydrophobic Down absorbs less moisture than untreated down. This keeps you warmer over a greater range of conditions, and allows it to dry and restore performance faster.
  • Nikwax Hydrophobic Down is formulated to be easily retreated at home using Nikwax DownWash and DownProof.
  • Water-based formula that's fluorocarbon-free and safe for you and the environment.
  • SynergyLink Connectors: Integrate the bag with a mattress for optimal comfort and efficiency; removable for versatility.
  • ThermaCapture Seams: Trap radiant body heat and retain warmth without adding bulk or weight.
  • Zoned Insulation: Maximizes warmth and saves weight.
  • Toe-asis Foot Warmer Pocket: Rapidly warms cold feet.
  • Quilt and Blanket Loops: Customize your sleep system by layering our quilts or tech blankets for increased warmth.
  • Additional features: Heat-trapping draft collar, full-length zipper draft tube, snag-free zipper, cinchable hood and external zip pocket.
  • Stuff sack and storage sack included

Questar HD prod shot

Richard Prideaux head shot  © Richard Prideaux

About Richard Prideaux

Richard Prideaux is the owner of established North Wales outdoor skills training and activity business Original Outdoors. He spends on average one night per week sleeping in a forest, up a mountain or on a beach somewhere in the UK and further afield and the rest of the time teaching navigation, foraging, tracking and other wilderness skills.

For more info see

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