Rab Ionosphere 5 Sleeping Mat Review


Our Rab Ionosphere 5 Sleeping Mat Review explores a highly technical mat with advanced features and innovative design. We hope you find it useful.


For many decades Rab have been know as a world leader in sleeping bag design and manufacture. This, of course, along their clothing and equipment expertise. Recently, they have also started to a produce a range of sleeping mats. As usual, Rab don’t do things by halves. There are various models in the range and all feature cutting edge technology and attention to design detail. We’ve been testing their Ionosphere 5 models and are happy to offer this review.

Size Comparison With One Litre Nalgene Bottle


Rab describe the Ionophere 5 as an ultralight and packable mat perfect for mountain expeditions where every gram counts. It is designed specifically to offer exceptional warmth and comfort. Let’s first consider the construction and materials used.


The main fabric of the Ionosphere 5 is 20 denier recycled polyester with an internal TPU coating and a fluorocarbon free DWR (Durable Water Repellent) outer coating. Internal insulation is offered by 160 gsm Stratus recycled polyester. The upper outer surface of the mat also includes a grip print designed to minimise sleeping bag slippage.

The Ionosphere also incorporates Rab’s TILT technology. In simple terms this is a silver reflective layer within the insulation designed to reflect heat back towards the user. I’ll add more detail on this technology later.

Design Details

The Ionosphere comes in 2 sizes. The regular size (tested) has a tapered mummy shape and measures 183x51cms. There is also a more rectangular shaped large/wide model that measures 196x64cms. Both models have an inflated thickness of 8cms. The focus of this review is the regular version.

The shaping of the mat is key to its design. The outer chambers are deliberately oversized to keep the sleeper in the centre. It then has a defined taper that will match the shape of a mummy style sleeping bag.

Other Features

The mat inflates and deflates via a low profile 2 way valve. A pump sack for mat inflation is included. The mat also comes with a storage bag and a repair kit. The weight for the regular is 550 grams and it has a packed size of 23cms x 11cms. The total weight for the mat, pump sack, repair kit and storage bag came in at 662 grams on our scales. For reference, the long/wide version weighs 810grams and has a packed size of 28cms x 12cms. The regular version costs £170 and the long/wide version costs £190. Both models have an R value of 4.8.

Grip Pattern Detail

In Use

Standard or Long/Wide?

As mentioned, this Rab Ionosphere 5 Sleeping Mat Review focuses on my experience with the regular version of this mat. I have no experience with the long/wide version although my research shows this is simply a longer and wider version and other features remain the same. So, this may be of interest once you have read about my experience with the regular version. Otherwise, all the findings below relate to the regular version.

Packed Size

The mat arrives rolled up in its storage bag and is a little bigger than the size of a one litre Nalgene bottle (please see photo for reference). The storage bag is quite clever as the mat can be tucked inside easily once rolled and then a flap closes over the top and seals with elastic straps. It’s a simple way to pack the mat and works as bit like a burrito. The pump sack and repair kit also fit inside (there is a small internal pocket for the repair kit).

Once opened, the mat unravels to reveal a lime green colour with a grey underside. It is a really nice colour. The grip print is obvious on the top of the mat. The shape is a defined mummy shape that sits reasonably narrow at the top and more narrow at the bottom.

Stratus R Insulation & TILT Layer Close Up

2 Way Valve

The low profile 2 way valve is positioned underneath the mat. This has a 2 stage action so it can be opened one stage for inflation and a second for rapid deflation. The mat can be inflated easily using the included pump sack or other low pressure pumps can be used. It takes about 5 sack fulls from the pump sack (depending on how full you get the sack each time). I’m a big fan of small battery powered pumps like the Flextail 2 when weight isn’t a concern. Rab don’t recommend inflating the mat by mouth as moisture may accumulate inside.

Luxurious Comfort

Once inflated, the mat thickness is a hefty 7 cms thickness. This offers luxurious comfort and means there is no chance you will touch the ground through the mat (providing it is sufficiently inflated of course!). It also makes it very comfortable if you are side sleeper. The mat will form comfortably to the shape of your body and the bony bits will be well supported.

Narrow Width Helps With Space In Narrower Tents

Oversized Baffles

The oversized end baffles are also very defined. These act as a scoop to keep the body central and in my experience they really work well. They also give a lovely feeling of being enclosed by the mat as it curves up slightly on each side.

Grip Print

I am quite a restless sleeper and also appreciate the grip print on the upper surface. This really dos seem to minimise the tendency for sleeping bags to slide around. Infact, I would have liked these on the bottom of the mat too. That might have kept the mat from slipping around on tent groundsheets too.


Deflating and stowing the mat after use is a breeze. You just open up the second stage of the valve, fold the mat lengthways into thirds and then roll it from the foot end. I have found it easy to get it stowed and rolled in one go rather than some mats that need a second or third roll. Even better if you have a pump like the Flextail as this will suck the air out for you.

Pump Sack In Use

Insulation Methods

Mat insulation levels are commonly given as an ‘R’ value. R value refers to a material’s ability to resist heat flowing through it at a certain thickness. The higher the R-Value, the better it can resist heat transfer. There is an international standard for R values (VALUE STANDARD ASTM-F3340-18) which helps buyers understand which product is suitable for their needs. The lower the R value the lower the insulation level. An R value of 1 – 2 may suit summer temperatures. For a winter mat you ideally want a mat with a value around 4 – 5. So, at 4.8, the Ionosphere offers very high levels of insulation suitable for consistently cold conditions.

Rab achieve this high insulation level in several ways. There is some insulation value when the sleeper warms the air within the chambers of a mat. However, to get anywhere near 4.8 more is needed. Inside the Ionosphere chambers Rab have used synthetic Stratus R insulation. This is a 100% recycled post-consumer material that traps as much air as possible. Stratus R, says Rab, offers superior warmth for its weight, retains warmth when wert and dries quickly.

Oversize End Baffles

TILT Technology

Alongside that, the Ionosphere incorporates TILT technology. TILT stands for Thermo Ionic Lining Technology. Rab explain this as a ‘radical, heat retaining tech that works like an emergency blanket reflecting heat back towards your body’. Rab have incorporated the TILT layer into the insulation.

As a user, it is hard to assess the internal insulation, the TILT layer, We do have the assessment of the R value as a measure. Otherwise, we can only say whether a mat is keeping us warm or not. My test period for the Ionosphere has largely been the warmer summer months and so many mats would have served my well enough.

Assessing Insulation Levels

However, I did have the chance to test the mat while bivvying in the Alps. One of these nights was spent sleeping directly on the snow of the Vallee Blanche. I paired the mat with a Rab Mythic 600 (I reviewed this sleeping bag here) and was very comfortable. The general temperature would have been somewhere below freezing, but sleeping on ice would mean maximum chance for conductive heat loss. I would certainly rate the Ionosphere 5 for challenging temps.


I have found the Ionosphere 5 extremely comfortable, but it is also important to consider whether the sizing will suit you. At 5’8″ and with a 38″ chest, I find the length and width just right. However, if you are significantly taller and broader you may want to consider the long/wide version. Ideally, I would suggest you try and make the opportunity to check the mat sizes first.

The narrower size does offer advantages if it works for your body shape. It helps to significantly reduce weight and pack size. It also means the mat fits well inside a tent or any more confined space. This would be especially noticeable if you have a few mats lined up inside a tent or on a narrower bivvy ledge.

Rab Ionosphere 5 Valve


Design Innovation

My Rab Ionosphere 5 Sleeping Mat Review shines a light on another innovative Rab product. When they bring a new product range to market, Rab never do half measures. This is no different. The Ionosphere 5 has many great design and technology innovations. It also offers exceptional performance and quality construction. Sustainability is also at the core of everything Rab does. The use of Fluorocarbon free coatings and recycled fabrics and insulation sets the industry standard for other manufacturers to follow. It also means purchasers are minimising their environmental impact.

Reliability & Durability

If your adventures take you to very cold environments and you need a mat that will insulate superbly while offering reliability and durability, the Ionosphere 5 is should be high on your list. It also benefits from design details that should help you get the best quality sleep for your mission. You even have the option for something longer and wider if needed. Full marks to Rab on this product. Rab have produced a useful video guide to the Ionosphere 5. Please have a watch below. Full details on the mat can also be found on their website here.

Hopefully you found this Rab Ionosphere 5 Sleeping Mat Review useful. We test a range of products and our reviews can be found on our website reviews section here. We’ve also worked with Rab for many years and have tested various products that might be of interest. This includes cold weather clothing like the Mythic Ultra jacket tested here. We have tested items from their running range such as the Ultra Jacket reviewed here and the Veil 2 Vest tested here. Finally, we have tested some of their rucksacks such as the Ascendor 28 reviewed here. Any Rab reviews can be found by using the search tab at the top of the website homepage.