Ionosphere 5 Sleeping Mat – Regular

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Well made and offering excellent warmth-for-weight, the lonosphere 5 will appeal to trekkers and mountaineers

Rab says: 

For mountain expeditions where every gram matters, the Ionosphere 5 is ultralight and packable, yet loaded with the necessary tech to keep you warm in tough conditions. The TILT reflective film within the insulation reduces radiant heat loss, while the Stratus™ R insulation traps air to lessen heat loss through convection, ensuring you can recharge for tomorrow even when the temperature plunges.

The tapered mummy shape is economical on weight, keeping pack size to a minimum. Oversized outer chambers ensure you stay central on the mat as you sleep, and the soft-finish fabric features a graduated grip print to reduce sleeping bag slip during the night. Inflation and deflation are quick and easy thanks to the low-profile two-way valve and pump sack.

The Ionosphere 5 is built using 100% recycled insulation, recycled fabric and a fluorocarbon-free DWR, and offers a superb warmth-to-weight ratio which won’t hold you back.

Our Verdict

This is a very comfortable mat, it’s 8cm thick, so it works well for side sleepers; the two outer baffles are oversized, which helps to keep you on the mat if you are a restless sleeper. It’s a tapered shape which helps reduce weight, but I prefer a rectangular design as I seem to stay on the mat better. The TILT (Thermo logic Lining Technology) reflective film, which the mat is lined with, helps reduce radiant heat loss and improves the R-value, but most impressively doesn’t crunch or crinkle when you toss and turn; the mat is effectively silent.

It’s not the lightest mat in this price range; however, it is definitely the most robust and is very well-made.

The pump sack is the most impressive I have seen; it inflates easily, holds a lot of air, and only weighs 71 grams. The elephant detailing is also a nice touch. The flat-bottomed design takes up little floor space, so pumping it up in a confined tent is painless. It took three sacksful of air to inflate the mat fully.

I am also a fan of the design of the bag the mat comes in; it’s an ergonomic and stylish cover that holds the mat well and incorporates a small repair kit tucked away, so you will always have it handy if you unexpectedly suffer a puncture.

– Reviewed by Ultralight Outdoor Gear

Features

• 20D Recycled Polyester outer fabric with internal TPU Coating and fluorocarbon free DWR
• Stratus™ R 100% recycled polyester insulation 80gsm with TILT
• Stratus™ R insulation traps air and reduces heat loss from convective currents
• TILT reflective film within the insulation helps reduce radiant heat loss
• Lightweight construction uses air and insulation for superb warmth-to-weight ratio and minimal pack-size
• Oversized outer chambers help keep you centralised on the mat
• Graduated grip print finish on upper fabric reduces sleeping bag slip
• Tapered mummy shape to save weight
• Low profile two-way valve for easy inflation and deflation
• Pump sack included for rapid and hygienic inflation
• Roll-away stuff sack with repair kit included

Specifications

• Weight: 548g
• Dimensions: 183x51cm
• ASTM R-Value: 4.8
• Thickness: 8cm
• Packed Size: 23cm x 11cm (9in x 4.3in)

ASTM R-Value

From 2020, there is a new industry standard for measuring the R-value (level of insulation) of sleeping mats – ASTM F3340-18. This new standard is the sleeping mat equivalent to the EN rating for sleeping bags.

You can now directly compare the R-value of mats rated using the ASTM F3340-18 with confidence that is a fair and accurate comparison between mats. In simple terms, the higher the R-value, the warmer the mat.

In general terms, an R-value below 2.0 is for summer use, 2.0 to 4.0 is for cooler 3 season use and 4.0+ is for winter temperatures. This will be also be dependent on your sleeping bag, how cold you sleep etc. Please contact our customer service team if you need advice on choosing the right mat for your activity.

Material & Construction

• 400D/20D 100% Recycled Polyester with TPU coating

Help & advice:

• The Ultimate Guide to Choosing an Ultralight Sleeping Mat
• Time-Saver Guide to Choosing a Sleeping Mat
• About Rab
• Rab Sleeping Mat Guide
• Rab Sleeping Mat Technology Explained
• Rab Sustainability and Responsibility
• R-Value Explained
• Recycled Content in Outdoor Gear