NEMO Siren 45 Quilt Review

NEMO Siren 45 Ultralight Quilt Review

The NEMO Siren 45 is a bed-style lightweight quit that weighs 21 oz and is insulated with 850 fill power RDS down. It’s an updated and redesigned version of the NEMO’s 30 degree Siren Ultralight Down Quilt, which has horizontal baffles instead of the new vertical baffles found on the Siren 45. The vertical baffles are a more efficient way to distribute the down insulation in a warmer weather quilt as well as being less expensive to manufacture.

NEMO Siren 45 Quilt


Warm Weather Quilt

Suitable for backpacking and camping, the NEMO Siren 45is a bed style down quilt that provides a comfortable sleep experience for that you can count on with a simple pad attachment system that is easy to tailor for your needs

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Specs at a Glance

  • Temperature rating: 45 degrees F \ 7 degrees C
  • Weight: 21 oz \ 600 g
  • Fill weight: 10 oz \ 285 g
  • Insulation: 850 fill power down RDS (Duck)
  • Liner and Shell: 10D Nylon Micro Ripstop w/ DWR, 10D Nylon Ripstop w/ DWR
  • Gender: Unisex
  • Girth 53″ x 48″ x 39″ (shoulder, hip, knee)
  • Length: 78″ (fits up to 6′ 0″ in height \ 183 cm)
  • Compressed volume: 2.16L (compression sack included)

The Siren 45 is designed to wrap around an inflatable sleeping pad in order to create a bed-like sleeping experience. It has a rectangular foot box and wide sides that wrap around the edges of your pad to block drafts. It also comes with a rudimentary pad capture system to hold the pad in place, although you can probably dispense with it in warmer weather when cold draft protection is less of an issue.

NEMO Siren 45 Pad Capture System

There’s nothing to prevent you from using the Siren 45 as more of a backpacking quilt, where you lie on top of a pad instead of sliding it inside the bag, or as a top quilt in a hammock without a sleeping pad at all. It’s certainly lightweight enough for backpacking, weighing just 21 oz, and it compresses down to a minuscule  2 liters when packed. But it’s probably best viewed as an alternative to a mummy sleeping bag for ground sleepers and one step less confining than NEMO’s innovative spoon-shaped sleeping bags, which were really the first sleeping bags specifically designed for side-sleeper use.

Pad Capture System

When you slide an inflatable sleeping pad into the Siren footbox, there’s still plenty of room inside the quilt for your feet, regardless of whether you’re a back sleeper or a side sleeper. However, it can be frustrating to get the tension on the string-based attachment system right so that you have enough room between the quilt and the pad to slide in from the head end. Very frustrating, in fact, since you have to flip the pad upside down to make any adjustments, which can be problematic in a two-person tent with another occupant.

The NEMO Siren has little plastic clips sewn into the side of the quilt which secure the draw-string in place.
The NEMO Siren has little plastic clips sewn into the side of the quilt which secure the draw-string in place.

My advice is to remove the string entirely and replace it with two or three horizontal pieces of elastic cord that will expand and contract as needed. This also makes getting the pad in and out of the footbox and past the elastic cords much easier than if you keep the crisscrossed static cord that comes with the quilt.  There are six unobtrusive plastic clips sewn into the quilt’s seams. Simply string three pieces of elastic cord across them before you leave to go camping, rather than trying to configure this in a tent.

The top of the quilt has two metal snaps behind the neck to hold it closed around your neck, but you really only need the top one. Once you’ve slid your feet and body under the quilt, you’ll snap one of these around your neck and lie down on the pad. They’ll keep the upper part of the quilt in place, including the area around your shoulders.

Quilt Neck closure
The neck closure has two adjustable cords.

There are also two adjustable cords sewn into the top seam of the quilt. These are used to tension the top so that it closes securely around your neck and blocks out drafts. They’re both easy to reach while you’re lying inside the quilt and help create a virtual draft collar around your neck when tightened. They’re much easier to use than the single neck closure cords found on many ultralight backpacking quilts and hold their tension all night.

Comparable Bed-Style Down Camping Quilts

Make / ModelWeightPrice
Exped HyperQuilt 3618 oz$219
NEMO Siren 4521 oz$270
NEMO Siren 3019 oz$370
Sierra Designs Nitro 800 /3520 oz$250
Sierra Designs Nitro 800 /2025 oz$280
Therm-a-Rest Corus 3220 oz$200
Therm-a-Rest Ohm 32 UL18 oz$370
Zen Bivy Light Quilt 2523 oz$259


The NEMO Siren 45 is a comfortable warm-weather camping quilt that provides a bed-like experience for people, especially side-sleepers, who find a hooded sleeping bag too confining. The Siren is different from most ultralight backpacking quilts because you slide an inflatable sleeping pad into it, rather than lying in your quilt on top of it. It has an extra-large foot box that wraps around the pad and keeps it securely in place and extra-wide sidewalls that are designed to wrap around the sides and underneath your pad to prevent any side drafts from chilling you.

The resulting experience of sleeping in the Siren 45 is very different from that of an ultralight backpacking quilt which does not “design-out” cold drafts to such a great extent and requires more expertise and experience to use. If what you’re looking for is something that is less intimidating to purchase and more predictable to use than a backpacking quilt, I think you’ll be pleased with the Siren 45. It is a well-made, comfortable, and warm camping quilt to sleep under, easily vented if you’re too warm and easy to snug down if you need to ward off a chill.

Disclosure: NEMO provided the author with a quilt for this review.

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  1. What size pad works with the Siren?

  2. You mention that this uses duck down instead of goose down. Any comments on the difference between the two?

  3. In the photo at the top of the column, do I spy, with my little eye, that you’re wearing the Montbell Down Balaclava (which you’ve also reviewed)?

    If so, in a great coincidence, we’ll be using the same setup. Before I found the balaclava review, I had purchased one and love it as part of my quilt system. Now, a few days before finding this review on the Siren, I had ordered this quilt – mostly because, as a side sleeper, the vertical baffles seemed like a good idea for the reason you also mention. I just got it yesterday, and will post again after I’ve taken it out a couple of times. Based on what I see in the living room, it looks well made, and I crawled into it to get an idea of the fit – it looks roomy, with lots of edges to tuck under me. I did pull the string back system off; it had a high PITA factor. I may add elastic strips with those little plastic lanyard clip-hooks on each end, if I find I need a pad attachment rig.

    My logic is that a 40-degree bag should keep me warm to about 30-degrees if I’m wearing midweight long johns and a down jacket and pants (in my case, Montbell Superior models), and using the hood on the jacket with the down balaclava. I’ll be sleeping on a Nemo insulated Tensor which I know is good on cold ground to 25-30 degrees from prior experience (with a quilt system.) That will give me a single versatile system for all the trips I might take. (At 70, backpacking only for pleasure a couple or three days at a time, I’ve decided I won’t go when nighttime lows are forecast to be below 35 or about 70.)

    I’ll post again, probably more toward spring, after I have some field experience with it.

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