Sea To Summit Thermolite Reactor Compact Plus Sleeping Bag Liner | Review - Outdoors Magic

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Sea To Summit Thermolite Reactor Compact Plus Sleeping Bag Liner | Review

Nic Hardy tests out the Sea To Summit Thermolite Reactor Compact Plus – a sleeping bag liner that boosts the warmth of your current bag, whilst prolonging its life

My current winter sleeping bag is the single most expensive item of camping kit I’ve ever purchased; more expensive than my four-season tent and sleeping mat combined in fact. So it makes sense to protect my bag and extend its life as long as possible to get the best value for money.

When I’m crawling into my bag sweaty and dirty from a long hike, the crucial part of my camping set up is actually my sleeping bag liner as it’s what protects the inner of the sleeping bag from potential dirt and/or odour ingress.

“The crucial part of my camping set up is actually my sleeping bag liner

I wild camped 74 times last year and I have experienced my fair share of camping ‘fails’ but my decision to use a liner with my bag has not been one of them. This winter I decided I needed to transition away from my traditional silk liner and try something new.

I saw the switch as an opportunity to add further warmth to my sleep system as my sleeping bag starts to age. After considering fleece and merino, I was intrigued to try Thermolite (a synthetic insulation) and found in this – the Sea To Summit Thermolite Reactor Compact Plus.

The liner is made of Thermolite, a synthetic form of insulation used in outdoor clothing and kit which is designed to offer warmth and comfort without compromising on weight. As a long distance walker who wild camps regularly, keeping pack weight to a minimum is of utmost important to me and is a key factor when looking to invest in new kit.

Comfort is also important when it comes to sleeping in the outdoors and replicating the feeling of being in my own bed is the best way to increase the chances of a restful sleep during a multi-day adventure. The liner has a soft ‘duvet like’ feel, which is great for those who have tried silk/nylon and don’t like to slip and slide around. The Thermolite fabric is comprised of hollow-core fibres which insulate by trapping air and wicking moisture away.

“I found the liner to be slightly shorter than I expected, although the material was stretchy”

Sea to Summit market this liner towards users under 6ft tall. At 5ft 7inches, I found the liner to be slightly shorter than I expected, although the material was stretchy, I could pull it over my shoulders but was struggling to get it further up my face without my feet feeling constricted at the other end. I did find the liner very wide towards the opening and would have preferred to lose some material from the width to gain a bit more length.

Sea to Summit claim the Compact Plus adds up to 11°C of warmth to a sleeping bag. If the cold particularly affects you, you might want to go for the Extreme model in the Sea to Summit Thermolite range, which boasts up to 15°C extra warmth for an extra 136g in weight. Alternatively, if you think the Compact Plus might be too warm for you, the standard Reactor liner weighs in at a total of 248g and offers up to 8°C to your bag.

Like many sleeping bags, the liner is not the same width from top to bottom. It tapers towards the feet which is perfect for those with a mummy shape sleeping bag. This type of design is both weight and space saving, but for those who like to fidget, starfish or generally prefer a roomier bag for the feet and knees, this liner might be too restrictive for you.

Interestingly with this design, there are two different weights of fabric used. The heavier of which is designed to keep the core temperature of the user as high as possible around the torso area, whilst also giving a boost to the feet and toes. These panels are 110g/m2 Thermolite, whilst the rest of the liner is 80g/m2 Thermolite.

A gripe of mine is when an outdoor product comes in a stuff sack and it’s impossible to get the product back into the sack after the first use but that’s not the case with this product. It rolls easily into the lightweight stuff sack ready for the next use.

Whether you’re a multi-day endurance adventurer or a once in a blue moon camper, everyone appreciates a good night’s rest. With so many variables that will affect your quality of rest – from the temperature, to the wind/rain noise, the evenness of the ground surface, tent buffeting, to sharing your space with a snorer – it’s important to limit their impact as much as possible. The performance of the liner is reviewed based on its ability to add both comfort and warmth to the sleep system.

The softness of the fabric was comforting against my cheek and I didn’t get tangled up in it turning from side to side during the night. It was both cosy and warm during sub-zero winter nights in the wild, so it gets a thumbs up from me for performance.

Another great feature of this liner is that it can be washed far easier than a down sleeping bag. The liner washes really well and is quick drying, great for long distance hikers who need to get back on the trail.

The impressive weight to warmth ratio, coupled with its comforting feel, makes this liner a great choice.

Another plus for this liner is that it can be dual purpose: It can line your winter sleeping bag when it’s cold, or it can also act as a light blanket in summer months when a sleeping bag would be overkill, for example in hostels or huts.

It’s certainly heavier than many of the liners on the market, particularly the silk liner category – but in return it does offer more warmth and comfort so it’s a compromise many will chose to increase the odds of a good rest.

Full Specifications

First dual fabric sleeping bag liner / 110g/m2 Thermolite panels in core body and foot areas / foot and torso areas are warmer / compact, shorter design is ideal for women and youth / packs into its own Ultra-Sil stuff sack.

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