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The Hyperion has one of the highest warmth-to-weight ratios of any sleeping bag currently available. It features an ultra-high-quality 900 fill power down insulation, a boxwall construction and much more.
What is it made of?Insulation: The Hyperion uses some of the highest quality down available, rated at 900 fill power. Fill power is essentially how 'fluffy' the down is — fluffier down can occupy more space inside the bag, in turn keeping you warmer. You'll need more down of a lower quality to equal the same warmth as high quality down which makes the bag heavier and less packable. Therm-A-Rest aren't using any old 900 fill power down, though, this down is treated with a Nikwax hydrophobic coating, meaning it stays drier and maintains loft 60 times longer than untreated down. All down is also R.D.S (responsible down standard) certified, meaning the down has been collected from birds which have not been subjected to any unnecessary harm.
Fabrics: Both the inner and outer fabrics of the Hyperion are made from an ultra-lightweight 10D Nylon with a Ripstop weave. If you happen to get the bag caught on something sharp, only a very small area of the bag will rip thanks to the ripstop (see where the name comes from now?) weave. The outer fabric has been given a DWR (durable water repellent) coating to add further protection.
How is it constructed?The Hyperion features a boxwall construction, meaning the down is assorted into cubes and distributed around the bag. This means that, unlike a stitch-through construction, there are very little cold spots (areas for heat to escape). Traditionally this construction was only used on big bulky expedition bags, but thanks to the Hyperion's lightweight fabrics and high-quality insulation, it can be used with very little weight penalty. Therm-A-Rest cleverly place more down where you need additional warmth and less where you don't. The base and the sides, for example, only contain 30% of the bag's down, with the rest placed across the top of the bag.
What are its features?The Hyperion features elasticated connectors on the bottom of the bag — simply attach them to the bag via the included loops and loop them around your sleeping mat. This keeps both your bag and mat paired together!
Therm-A-Rest include both a storage sack and compression stuffsack with the bag. The former, as the name suggests, is for storage and the latter is used for transporting the bag. Try not to store the bag in the compression sack as this will reduce its efficacy the next time you need to use it.
How does it fit?Unlike most super-techy, lightweight sleeping bags, the Hyperion has a fairly relaxed, comfortable shape. There's plenty of room at the shoulders and hips to wriggle about, yet it's still tapered at the lower leg to increase efficiency.
- Lightweight construction
- 10D Nylon Ripstop fabrics
- Durable water repellent coating
- Nikwax hydrophobic insulation
- 900 fill power goose down
- Boxwall construction
- Comfortable, spacious fit
- SynergyLink Connectors
- Zoned insulation
How warm a sleeping bag do you really need? We’ve tried to help you by grouping our sleeping bags by their recognised comfort ratings. These are the ratings supplied by the brands that indicate the temperature at which you will remain comfortable whilst sleeping on an insulated sleep mat. After all, comfort is what you want when it’s cold and wet outside, and you’re all tucked up in your nice warm sleeping bag.
We always recommend that you choose your bag according to the coldest conditions you will experience; you can always unzip a bag if it is too warm, but trying to sleep when you’re too cold is just miserable. Bear in mind that we are all individuals, so we all feel the cold differently and that our own resistance will fluctuate depending on a whole load of factors, including how much we have eaten, whether we have consumed alcohol, whether we need a wee or what kind of mood we are in!
Sleeping bags do not generate heat; they only trap the heat we produce, so it is vital that you get into your bag when you are giving off warmth, don’t go to bed when you are cold, have a hot meal or a hot drink or do some brisk exercise to get you nicely warmed up.
Traditionally sleeping bag manufacturers provided their own temperature ratings based on their experience, the product's intended end-use and the perceived environment. However, each brand tested their bags in different ways, and it was hard to find a fair comparison between models. So, in 2005 a European standard for sleeping bag temperature ratings, EN 13537, was introduced to give consumers a comparable guide to sleeping bag performance across a range of brands and models. The ratings have four different temperature ratings to give you an indication of the bag's performance.
Comfort Rating: This is the temperature at which an average female should experience a comfortable night’s sleep. On average, women sleep colder than men, so this rating is some degrees above the "comfort lower limit" for a man.
Comfort Limit Rating: This is the lowest temperature at which an average male should experience a comfortable night’s sleep whilst laid down in a curled up position.
Extreme: This is a survival rating where the user is likely to suffer health damage such as Hypothermia. It should be treated with the utmost caution and not be relied on for general use.
However, the EN 13537 European Standard does not apply to down-filled sleeping bags with a fill weight of more than 800g; for those bags, you will have to rely on the manufacturer's experience and technical expertise, which is often more accurate!
Most reputable brands still use their own rating system alongside EN 13537, for instance, Mountain Equipment's “Good Night’s Sleep” and Rab’s “Sleep Limit”. These ratings are often the most accurate guide to the overall performance of a sleeping bag being used by an average outdoor enthusiast because they are based on years of expedition heritage, field trials, technological experience, and constant feedback.
But please bear in mind that all ratings are only a guide and, as mentioned earlier, there are a huge range of factors that can affect your comfort; if you are just not sure, it is always wise to go for a warmer model.
The biggest difference you can make to your overall comfort is to use an efficiently insulated sleeping mat. Once you get inside your sleeping bag, you instantly compress all the filling beneath you, greatly reducing its efficiency. Therefore using a quality sleep mat will ensure you are properly insulated from the cold ground, and you will be a lot more comfortable... Basically, there is no point in buying a top-quality sleeping bag if you are just going to lie down on the floor.