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Using a liner as a stand-alone ‘sleeping bag’
Ask Baz

Using a liner as a stand-alone ‘sleeping bag’

We’re often asked if you can use a sleeping bag liner instead of a sleeping bag in warmer temperatures.

Broadly, the questions fall into two categories: those end-users who are intending to sleep outdoors, either in a tent/shelter or under the stars and those end-users who are intending to sleep in a hostel.

For ‘outdoors’ users, the liners which would come into question would be the Reactor, Reactor Compact Plus, Reactor Extreme, Reactor Fleece, and the Adaptor.

For hostel sleepers, the Silk, Silk-Cotton and Expander liners would be appropriate.

When sleeping outdoors, the main factor to be aware of is moving air. The Reactor and Adaptor liners are primarily designed for use inside a sleeping bag, so they allow enough air to pass through their fabric to guarantee a comfortable night’s sleep in that configuration. Breezes and drafts in an outdoor situation will also pass through the fabric and rob you of the warmth you have generated. If you are inside a tent or shelter, this is less of a factor, but ‘under the stars’ you may need something to act as a windproof barrier laid over the liner; for instance a poncho or an ultralight sleeping bag cover.

The hollow-core Thermolite fibers and three-dimensional knitted structure of the Reactor series are very effective at trapping warmth. Providing you are dressed in dry base layer garments, in still air, you can expect a Reactor to work as a ‘stand-alone’ sleeping bag down to air temperatures of around 55°F/13°C and a Reactor Extreme will be comfortable down to around 50°F/10°C. An Adaptor will be comfortable down to a couple of degrees warmer than a Reactor.

When sleeping in a hostel, moving air is likely to be much less of a factor. Essentially, the liner is primarily providing a comfortable sleeping environment (and, of course, providing a hygienic refuge from less-than-pristine sheets and possibly bed bugs – see the blog post ‘Which liner should I choose’). Many hostel/backpacker’s hotel users will be sleeping in tropical or sub-tropical locations where there is no concern about maintaining warmth; in those locations a Silk, Silk-Cotton or Adaptor Liner is a comfortable haven at night which is easy to wash and quick to dry.

If you are hiking on one of the classic pilgrim walks, such as the El Camino Santiago, you may encounter temperatures closer to those discussed for ‘outdoor’ users above, If this is the case, an Adaptor or a Reactor would be the liner of choice.

6 thoughts on “Using a liner as a stand-alone ‘sleeping bag’

  1. avatar Baz says:

    G’Day Sarah – thanks for your question. 10°C air temperature (even in a bivy) is probably close to the lower end of what you would regard as comfortable sleeping in just a liner. At the other end of the scale, 20°C (especially if it is humid) could mean quite a lot of condensation inside the bivy.

    On balance, we’d probably recommend the Reactor liner – it will be (just) warm enough in the colder temperatures you mention, and will wick well enough to keep you comfortable (if it is kept away from fabric softeners during the wash cycle) in warmer temperatures.

    If you would like more details, email us at – please let us know which Gore-tex bivy you have, and where/what kind of conditions you would use the bivy/liner combo in.


    The Sea to Summit team

  2. avatar Sarah Wechsler says:

    I’m trying to pick a Reactor to use as a standalone bag inside a Gore-Tex bivy (so, still air) during the summer. Could you estimate temperature ranges (including maximum – I’m assuming a Reactor Extreme would probably be too warm on a 20 C overnight?) for your different liners like this, or recommend one that (ideally) would run comfortably from 10–20 C, closed up at the bottom end and open at the top of course?

    Mostly I’m looking to have something to sleep in that’s easier to wash than the bivy or a sleeping bag.

    Thank you!

  3. avatar Baz says:

    G’Day Robinya,

    Thanks for your question. Hostels in Australia and New Zealand vary from downright chilly to sub-tropical… Can you email us at and let us know your approximate itinerary?

    We’ll be happy to make recommendations for sleep options that will work for you.


    The Sea to Summit team

  4. avatar Robinya says:

    We will be coming to Australia New Zealand in January 2021. I am looking at liners to supplement potential sleeping spaces. We will be staying in some hostels.
    I am usually cold, will the silk liner be sufficient?

  5. avatar Baz says:

    G’Day Barry – thanks for your question.

    Given that temperatures in QLD and NT will not drop much below 20°C in May and June, you should be fine sleeping in a Silk Liner inside your one-person tent. Camping underneath your tarp may involve moving air (light breezes etc), and if this is the case, the Silk Liner may not be quite warm enough.

    If you would like more details, email us at and we will pass your questions on to our Perth, WA-based colleagues.


    The Sea to Summit team


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