The Therm-a-Rest Haven is a special type of sleeping bag that doesn’t have any back insulation. Called a Top Bag, all of the insulation in the Haven is located on top of your body and along the sides, because insulation and fabric you lie on can’t retain warm air and is just dead weight.
Designed to be ultralight, the Haven weighs 1 pound 7.8 ounces (684 grams) and contains 700 fill power down with a temperature rating of 20F. As a point of comparison, my 20F degree down sleeping bag, a Western Mountaineering Ultralite weighs 1 pound 13 ounces, so an appreciable weigh difference if you are trying to trim your gear weight.
The Haven does not have a zipper which helps save weight but makes the bag a little challenging to get in and out of. If you’re very thin, you could slide through the top of the bag past the hood to get in and out. My shoulders are too wide for this and I can only get in by sliding in from the back.
Sleeping Pad Integration
For maximum warmth, Therm-a-rest recommends that you slide your sleeping pad inside the Haven. Since I have to get in from the back, I start by sliding my pad into the Haven’s footbox, and then sliding my feet in on top of it. I enter the Haven from the back and pull my head into the hood.
Finally, I reach behind my back and fold up my sleeping pad in order to slip it under the elastic behind my lower back.
This is much easier to do with a thin Therm-a-rest pad like a Women’s Prolite instead of an Neoair Xlite (shown above), and if you are a large person, you want the extra space inside the Haven that the thinner pad provides. I like sleeping with the thinner Prolite pad inside the Haven the best, because the elastic around the Haven’s back hole forms a perfect seal with the pad and eliminates any side drafts.
The other option is to get into the Haven (again from the back) and simply lie on top of your sleeping pad. This does not eliminate side drafts however and Therm-a-Rest only recommends it as a warmer weather configuration. The Haven comes with a pair of straps that let you secure an external pad over the back hole, but these are only practical to use if you can slide in through the top hood. They tear off very easily however, so I’ve removed them entirely (1.2 ounces) and let the walls of a single person tent keep me on the pad.
The Haven has a hood like a sleeping bag, but it has a curious design. It has a cinch cord, so you can pull the perimeter of the hood tight, but this has the effect of lowering the top of the hood over your eyes rather than pulling it in closer to the sides of your head like a traditional mummy bag.
The same cinch cord is also used to control the space between your chest and the top of the bag, but does more to flatten the hood and narrow the breathing space, rather than narrow the space around your chest. It would be better if the hood and size of the chest opening were controlled separately as they are on most sleeping bags.
No Draft Collar
Unlike many mummy bags, the Haven lacks a draft collar which is a tube of down or synthetic fill that drapes across the top of your chest and prevents the hot air heated by your body from flowing out around your neck when you move at night, the so-called “bellows effect.”
If you plan on using the Haven in 20-30F degree weather, the lack of a draft collar is unfortunate because you will be cold at night. One way to mitigate this is to make a poor man’s draft collar by tying a sweater or insulated jacket around your neck so that it fills the space where a draft collar would normally be placed. This works very well and is a neat little trick for warming up a sleeping bag at the low end of its temperature range.
On the flip side, I can understand why Therm-a-rest left the draft collar off the Haven – because it would make the bag much too hot in warmer weather. Without a zipper there is no effective way to vent the Haven and having a draft collar would make it even more unbearably hot in warmer weather.
A Plus for Side Sleepers
It’s easy to sleep on your side in the Haven because the hood is flat and wide and will vent your exhalations without collecting condensation. Contrary to what you might expect, rolling onto your side does not bring the back pad or back of the Haven off the ground – you simply rotate inside, as long as the pad you are using is inside the Haven and held in place by the elastic surrounding the back hole.
I have taken the Haven down to the mid 30’s at night and remained quite comfortable, wearing long underwear, a fleece hat and a fleece top. I reckon I could take it down at least into the high 20’s with a poor mans draft collar to keep the body heat from escaping out around my chest.
However, when temperatures are in the high 50’s, the Haven has a tendency to become a little to warm to sleep in without removing more of my sleeping clothes. In even warmer summer temperatures, I would avoid using the Haven for sleeping because it is impossible to unzip and vent. The hood and collar also makes it difficult to use as a quilt or blanket because they get in the way of draping the Haven over your chest and shoulders.
The Haven works best when used in cooler temperatures (35 – 55) with a thin pad than can be slipped into the top bag and prevent any side drafts from reaching the occupant. Without a zipper, the Haven is difficult to vent in very warm weather when a regular lightweight sleeping bag or down quilt would be a much more flexible option. Still within a cooler temperature range, the Haven is a comfortable sleep system, and a lightweight one, provided you use a lightweight sleeping pad.
- Good for side sleepers
- Provides more head insulation than a regular sleeping quilt
- Narrow temperature range/hard to vent in warm weather
- Sleeping pad straps are easy to pull off back of bag where sewn
- Doesn’t have a separate draft collar
- Thick sleeping pad limits interior room if slid into the footbox
Disclosure: Therm-a-Rest provided Philip Werner (SectionHiker.com) with a sample Haven Top Bag for this review.
- Size Tested: Regular
- Weight: 22.8 ounces / 648 grams (on the SectionHiker.com scale)
- Fits: Up to 5′ 10″ (178cm)
- Girth Shoulder: 60 in / 152.4 cm
- Girth Hip: 60 in / 152.4 cm
- Girth Footbox: 40 in / 101.6 cm
- EN13537 Comfort: 30 F / -1 C
- EN 13537 Comfort: Limit 20 F / -6 C
- EN 13537 Extreme: -10 F / -23 C
- Fill: 700 Goose Down
- Fill Weight: 10.6 oz / 300 g
- Liner Fabric: 100% Nylon Taffeta, 30 denier. Fabric is calendared to achieve down-proofing.
- Shell Fabric: 100% Nylon Riptop, 20 denier, DWR finish