ActiveOutdoorsCampingKelty Cosmic SI Mummy Sleeping Mat Review: A warm, robust camping padA warm, robust and comfortable camping mat for 3-season sleepoutsWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.(Image credit: Mark Mayne)T3 VerdictThe Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-ValueReasons to avoid-On the heavy side-Bulky packsizeWhy you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
ActiveOutdoorsCampingKelty Cosmic SI Mummy Sleeping Mat Review: A warm, robust camping padA warm, robust and comfortable camping mat for 3-season sleepoutsWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.(Image credit: Mark Mayne)T3 VerdictThe Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-ValueReasons to avoid-On the heavy side-Bulky packsizeWhy you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
A warm, robust and comfortable camping mat for 3-season sleepouts
When you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.
(Image credit: Mark Mayne)T3 VerdictThe Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-ValueReasons to avoid-On the heavy side-Bulky packsize
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
T3 VerdictThe Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-ValueReasons to avoid-On the heavy side-Bulky packsize
T3 VerdictThe Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.
T3 Verdict
The Kelty Cosmic SI Mummy Sleeping Mat offers good warmth and a large sleeping area, but the penalty is weight and packsize. However, the build quality is strong too, making it a decent choice for the three-season camper.
Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-ValueReasons to avoid-On the heavy side-Bulky packsize
Reasons to buy+Good build quality+Brass valve+Large sleeping area+Good R-Value
Good build quality
Brass valve
Large sleeping area
Good R-Value
Reasons to avoid-On the heavy side-Bulky packsize
On the heavy side
Bulky packsize
Why you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
Why you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
Kelty Cosmic SI Mummy deals
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The Kelty Cosmic SI Mummy Sleeping Mat is a self inflating camping mat that takes aim at all levels of camper, and in three of the four seasons to boot. Available now, the Kelty Cosmic SI Mummy Sleeping Mat is priced at a UK RRP of £69.99.
Kelty Cosmic SI Mummy Sleeping Mat Review: Design and build
The Kelty Cosmic SI Mummy Sleeping Mat follows a familiar pattern to many ‘self inflating’ sleeping mats, with an outer fabric shell and a foam inner layer that inflates the mat when unrolled. The outer fabric is 20D nylon ripstop and feels fairly robust to the touch, and another strong point on the robustness scale is the valve, which is made from brass - not lightweight, but certainly robust. Sometimes, however, a little extra weight is worth carrying for reliability at the end of a day on the trail. Read on to see where this sleeping pad fits into thebest camping matsavailable today.
Today’s best Kelty Cosmic SI Mummy deals$59.95ViewWe check over 250 million products every day for the best prices
Today’s best Kelty Cosmic SI Mummy deals$59.95ViewWe check over 250 million products every day for the best prices
Today’s best Kelty Cosmic SI Mummy deals
$59.95View
$59.95View
$59.95View
$59.95View
$59.95
$59.95
We check over 250 million products every day for the best prices
We check over 250 million products every day for the best prices
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
The Kelty Cosmic SI Mummy Sleeping Mat is an unusually generous 198 x 60 x 2.5cm when unrolled, and packs down to a standard-if somewhat chunky 31 x 21cm roll - with some help from a pair of elasticated straps.
The mat gets an ASTM R-Value of 3.9 - that’s based on the new (2020) R-value measurement standard, snappily known as ASTM F3340-18. On the flipside, the weight of the Kelty Cosmic SI Mummy Sleeping Mat is headed precariously close to the kilo, weighing in at a stolid 920g (excluding stuff sack).
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
Kelty Cosmic SI Mummy Sleeping Mat Review: Performance and comfort
Comfort is very much the watchword for the Kelty Cosmic SI Mummy Sleeping Mat, as there are no concessions to anything else, like lightness or packability. The unbroken foam sheet inside supports just like a mini-mattress, and the quilted surface effect adds a touch of luxury. There’s no cutouts in the foam, which gives a consistent mattressy texture, and the fabric isn’t unpleasantly slick. The generous sleeping area is also useful (as long as your tent floor is big enough), helping to prevent the dreaded ‘night-time rolling off onto the cold floor’ issue all campers will be familiar with.
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
The Kelty Cosmic SI Mummy Sleeping Mat self-inflates in about 30 minutes or so, needing a couple of puffs to firm it up, like most similar mats. The brass valve is a strong point - a simple twist-lock plastic collar is easy to operate and intuitive, even in the dark. The metal construction should easily outlast the rest of the mat too, and in fairness cheaper mats often suffer from valve issues, so props to Kelty for nipping that potential issue in the bud.
Performance is a bit more of a mixed bag - the ASTM R-Value of 3.9 is perfectly respectable for three season use, and indeed could at a bit of a push be used in winter, perhaps with a cheap closed cell foam mat. The problem really is the weight, which at just under a kilo is on the heavy side. Of course, for car camping and short trips this isn’t an issue, but at this price point you could easily pick up a Thermarest Prolite Three (for example) and save at least 200 grams for a similar sized mat for just £20-ish more. Or indeed try a Vango Trek Pro 3 Standard Sleep Mat, and save weight and a chunk of cash.
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
Kelty Cosmic SI Mummy Sleeping Mat Review: Verdict
As mentioned above, the Kelty Cosmic SI Mummy Sleeping Mat really falls down on weight and price, being quite heavy and getting dangerously close in cost terms to some of the premium mats available. In itself, the Kelty is a perfectly decent mat, and certainly seems built to last, which is a key concern both for the wallet and the environment.
(Image credit: Mark Mayne)
(Image credit: Mark Mayne)
The R-value is enough to cover off most casual camping needs with ease, and the robust valve is ideal for the slightly less careful campers, and family-style environments. Overall it’s up to Kelty’s usual quality standards, but on the heavy side for backpacking and trekking applications.
Kelty Cosmic SI Mummy: Price Comparison
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