Mountain Laurel Designs Spirit Quilt 38° Review - The Trek (2024)

There are times when I’m happy to carry a quilt that is way warmer than it needs to be. My 20°F quilt is darn near guaranteed to sweat me out if I tuck it tightly, but it is easy to drape it loosely and I never need to worry about sleeping cold. However, sometimes I feel like that peace of mind isn’t worth the extra bulk and weight on my back. Sometimes all I want is the right tool for the job. The Spirit Quilt 38° by Mountain Laurel Designs is just that during the warmer months when the days are long and the mountains are in their hiking prime.

I picked up the Spirit 38° this summer after my beloved rainbow 30° quilt was lost in the mail. While I never considered carrying anything lighter duty than that, I decided to push my limits in the name of feeling like a wannabe UL badass. And with a bushy beard sprouting from my face as a result of my laziness, how cold could I really get? Nighttime lows in the high Rockies were right at my Spirit’s limit, so I was about to find out. The board was set, and I stuffed my pack. Would I regret carrying such a light quilt? Time would tell.

Mountain Laurel Designs Spirit Quilt 38° At-a-Glance

The MLD Spirit 38 is a lightweight synthetic quilt with a zippered footbox.

MSRP: $230 (As tested. $260 with optional poncho head slot.)
Weight: 17 ounces (As tested. 15-21 ounces based on chosen size.)
Temperature Rating: 38°F (Also available: 28° and 48°F)
Type: Quilt, opening zippered footbox
Insulation: Synthetic Climashield APEX
Fabric: 10D nylon inner and outer
Country of Origin: U.S.A.

Intended Use

The product description on the Mountain Laurel Designs website has a lot of useful things to say, including the following disclaimer: “The Spirit Quilt 38°, is a true Ultra Lightweight Specialists tool; if you are new to backcountry sleep quilt systems and their use, please read the entire product description and specs before adding to cart.” Now, I wouldn’t use those words — Ultra Lightweight Specialist — to describe myself, but I get where MLD is coming from.

Their Spirit quilts, especially their lighter models (38° and 48°) aren’t designed for just anyone. Without understanding the limitations of such a piece of gear, it can be dangerous to substitute a lightweight quilt for a classic mummy sleeping bag. With the former, there is a learning curve involved, and one needs practice to extract the maximum warmth from such a specialized design. So what does that mean? The Spirit Quilt, and specifically the 38°F version, is for backpackers who want a durable, lightweight quilt for warm conditions, and aren’t afraid to learn how to use it properly.

Circ*mstances of Review

October along the Gila. Good living.

I tested my Spirit 38° from the middle of summer and into the colorful explosion of autumn. Summer lows in the high Rockies were similar to October lows along the Gila River in New Mexico, and I pushed this quilt to, and a bit past its listed temperature rating. Most of my nights under the Spirit were in the low 40’s (inside tent measurement), and I tried to sleep in as few layers as possible to generally and accurately characterize its insulating abilities. The quilt was also paired with a thrashed Zlite Sol (R-value of 2), which didn’t do it any favors with its barely passable ground insulation.

Furthermore, I’m 5’7” and used a size medium, which I think was a near-perfect fit. I would also consider myself a warm sleeper, so please take my warmth assessment with a grain of salt unless you burn hot as well.

Mountain Laurel Designs Spirit Quilt Features

Attach the Spirit to your sleeping pad with a single elastic strap. Nothing fancy or offensive here.

Optional poncho hole

If you’d like the ability to wear your Spirit like a poncho around camp, hands-free, then you can add a slot in the middle of the quilt to slip your head through. This’ll cost you $30 and your dignity, but might be a handy feature for you. My Spirit did not include this.

Zippered footbox

While the back of the quilt is always open, the footbox can be zipped closed from the toes to roughly the knees. Combined with the drawcord closure at the bottom, this allows the Spirit to have a closed footbox when you want to keep your feet warm. On hot nights, unzip and open it up into a flat, almost rectangular blanket.

Footbox plug

Unique to the Spirit, MLD includes a small insulated plug (same materials as the quilt), that is intended to be used to plug the small hole left by the drawcord at the toes. For minimal extra weight or fuss, this thing blocks drafts from blowing where they are least wanted.

Snap and drawcord neck closure

Like most/all quilts, a plastic snap button and drawcord help seal the quilt around your neck. This helps to reduce drafts and is essential at near-limit temperatures.

Synthetic insulation

Climashield APEX is a synthetic insulation that is manufactured in large, continuous sheets. This shape minimizes seams and stitching, which can introduce potential cold spots. While this technology doesn’t match the warmth-to-weight ratio or packability of most down insulation, it retains its insulating properties when wet, lasts a long time, and is easier to wash. And while it is derived from petroleum products, it dodges the sticky ethical questions that surround even ‘responsibly’ sourced animal products.

Underquilt ready

I like sleeping on the ground, so I’m not exactly sure what it takes to turn this quilt into an underquilt for a hammock setup, but apparently this is possible.

Pad attachment system

Simple and effective, the quilt clips to an elastic strap that encircles your sleeping pad. From there, one can open or tighten the quilt as desired to match the conditions. When the temperature drops, this can make a huge difference by blocking drafts and reducing excess dead air.

How’d It Do?

The fabric and neck closure of the MLD Spirit isn’t exactly plushy, but they get the job done.

Well, I didn’t die. In fact, I was always comfortable while using the Spirit 38°, and sometimes too warm when I chickened out and added clothing layers. So, as I hoped, it was the ideal quilt for summer in the mountains, or the shoulder seasons in warmer climates. It would have been perfect for the Florida Trail earlier this year, and, I imagine, great for the dead of summer on the AT.


The Spirit is a minimalist quilt that is pretty much free from extraneous comfort features. For instance, there’s no draft collar to improve the feel of the neck opening, and the outer/inner fabric are exactly the same. With more comfort-oriented quilts/sleeping bags, the inner fabric is often chosen for its next-to-skin feel, but that isn’t a priority for MLD. Instead, as described on their highly educational Fabric Mojo page, the Spirit’s 10D ripstop nylon was chosen for durability and strength. Its denser weave also contributes to the quilt’s warmth in ways that only the nerdiest gearhead will understand or appreciate (Hey, don’t look at me).

I bring all this up not to bash on the Spirit for being uncomfortable, but to highlight that plushy comfort is not the top priority. So if you like the finer things in life, then it might be worth tracking down a sleeping bag with more refinement. They exist and don’t necessarily weigh more.

Instead, MLD focuses on thermal efficiency. The Spirit is tuned to keep you warm for as little weight as possible, which is arguably more important than fabric feel depending on your priorities. Saving weight on your back increases comfort all day while hiking, and most people wear clothes to sleep anyway. Why do I care if the inner fabric is as soft as puppy fur if I’m still wearing my salt-crusted hiking shirt? That’s my, slightly gross view, at least.


Not really a fair comparison, but on the left is a 20°F down quilt. The MLD Spirit is on the right. The difference in loft is significant and the absence of baffles is obvious.

MLD breaks from other quilt and sleeping bag manufacturers by resisting the characterization of their quilts with a single pretty, and highly qualified, temperature rating. The true warmth of a sleep system relies on so many factors and the quilt is just one part of this, so I get it. Besides, there isn’t even a standard for testing quilt warmth ratings like there is for sleeping bags. So while this is as frustrating as a hipster explaining the difference between an americano and coffee, I appreciate MLD for not taking the easy way out.

Instead, they explain their assessment of the quilt’s warmth as it relates to clothing layers worn in conjunction. The Spirit 38 should keep you warm while wearing light baselayers down to 38°F. Add an insulated jacket, warm hat, and bivy/shelter, then you might be good down to 32°F. Add even more warm clothes and you might be good to 25°F. Of course, the logic behind this makes sense and applies to all sleeping bags — wear more warm clothes and you’ll be warmer. Duh, makes sense, right? This truth is often overlooked.

In my experience, MLD has it close to dialed. I prefer to sleep in a hooded puffy or fleece no matter the temperature for extra coziness, but to test the Spirit, I slept in shorts and my hiking shirt on a couple of nights that dipped to around 40°F. I wasn’t cooking, but I slept comfortably. On similarly cold nights when I did don my jacket, I was warm enough that I didn’t need to fuss with the pad attachment system.


Here’s the footbox in all of its glory. The zipper and plug do a pretty good job of closing it up.

In all honesty, I prefer my quilts to have a closed footbox, and I only took a chance on the opening design of the Spirit because I’m not concerned about the temperatures in the 40’s for which it is intended. Never have I ever felt like a fully opening footbox would improve my life, and I’ve always been skeptical of the closure systems. In fact, the one time I borrowed a Revelation quilt from Enlightened Equipment, I could feel a puff of cold air sneaking in through the cinched closure every time I moved. It sucked. Feet are often the hardest part of the body to keep warm at night, so why purposely build in something that compromises this integrity?

Different quilt manufacturers approach this issue in different ways, and I admit that MLD solved the problem. Attached to the footbox closure drawstring (so it won’t get lost), is a tube of insulation about the size of a hot dog bun or burrito off the Taco Bell value menu. Cinch up the footbox around this plug and it blocks drafts. This is a simple and effective, albeit inelegant, solution.

When the plug popped out before falling asleep one night, I immediately noticed a draft on my feet, which was all the confirmation I needed that it works. So, am I happy with the footbox design? I like that it blocks drafts, but I remain unconvinced that zippered footboxes are worth their weight. I have still never felt the urge to open it while I sleep, and that one time I popped my feet out to waddle around camp was mostly for novelty.


The Spirit 38 is a relatively light-duty quilt. Therefore, even though it uses synthetic insulation rather than down, it packs quite small. I can’t imagine anyone complaining about its packability and it is tiny compared to my 20°F synthetic quilt. Besides, when it comes to synthetic insulation, you can’t beat Climashield APEX. It’s the best we have whether you think it compresses well or not.

Synthetic vs. Down Insulation

The strengths and weaknesses of both down and synthetic insulation have been explained in a number of articles already. Broadly, down is lightweight and compressible, but it also approaches uselessness when wet and is expensive. Synthetic insulation is cheap and has good wet weather performance, but is heavier and more bulky than down.

Despite the drawbacks, synthetic insulation is a great choice for those who want fuss-free warmth in damp environments. On the PCT, a week of misty overcast conditions gradually saturated my down sleeping back night after night until its warmth was significantly compromised. This isn’t uncommon on the AT either where summer humidity can make it difficult to dry damp gear even on sunny days. So if you want to worry less, then consider synthetic.

Mountain Laurel Designs Spirit Quilt Pros

My partner hates how the footbox plug looks, and I don’t blame her, but it works.

Footbox plug: I think it is ludicrous to have a footbox that doesn’t completely prevent drafts. There are numerous ways to ensure that cold air stays out, and MLD’s is probably the least-sexy solution, but it works. That’s what matters.

Price: Synthetic products are significantly cheaper than their down equivalents, which is great for the budget-minded backpacker. The MLD Spirit is a high-quality quilt for a relatively low price. While my 38°F version likely won’t cut it as a do-it-all quilt, the Spirit 28 could be just that. So that’s a PCT-, CDT-, or AT-worthy quilt for just $245? Not too shabby.

Weight: There are lighter quilts out there, and some are even warmer than the Spirit 38. However, once you get to a certain point, it hardly feels like an ounce here or there matters. At 15-21 ounces, depending on the size, I’m more worried about getting my food quantity right than my Spirit when it comes to cutting weight.

Cruelty-free: I’m not here to push my vegan agenda, but even down produced in agreement with the Responsible Down Standard (RDS) is exploitative. Sure, it doesn’t allow for live-plucking, force-feeding, or other cruel practices, but it still permits the commoditization of living beings in a way that eliminates their consent and values their lives as less than our own. I’m not saying that geese need governmental representation, only that, as humans, our technological advances allow us to now choose compassion over exploitation. By replacing down with synthetic insulation, we avoid arbitrarily defining “responsible”, and eliminate an avenue towards animal exploitation.

Made in USA: Quality custom quilts made right here in the best damn country between Mexico and Canada. ‘Murica!

Mountain Laurel Designs Spirit Quilt Cons

Not many seams to speak of. That makes the MLD Spirit warmer, but also fussier.

Weight: Screw it, this can be a pro and a con. If you care about weight above all else, then you will probably wind up with a down quilt. But please, please, please, keep it dry.

Loose fabric: One of the strengths of the Spirit’s APEX insulation is that it comes in a single, continuous sheet. Sewing pokes holes in that fancy fabric and can contribute to cold spots where the insulation is compressed, so it’s more efficient when there is no need for baffles or quilting. The downside is that the large, unanchored panel can billow and get caught in odd ways. At worst, I struggle to get my clammy feet into position. However, once I’m there, it’s all good.

Highly specialized: The Spirit 38 isn’t the ‘one quilt to rule them all’. I’m thrilled to have it in my quiver for warm-weather trips, but I would feel limited if it was the only quilt I owned. For this reason, I view it as a luxury item for gear nerds or Florida Trail enthusiasts. You might be able to make the warmer, Spirit 28 work for almost anything, however, if you like what MLD is laying down but don’t already own a warmer option.

Final Thoughts

Wearing my MLD Spirit like this was a fun moment and kept my legs warm, but I’m still not fully onboard with the opening footbox.

The Spirit 38 from MLD has helped me reach my practical limit when lightening my backpacking kit for summer in the mountains. It is just enough quilt to keep me comfortable in mild conditions, and bringing it along has made a big difference to my backpack’s volume. While my 20° quilt provides a reassuringly foolish amount of warmth and is almost always overkill, there’s something that feels good about carrying no more than what I need.

However, while I could bring one of the many 40°F quilts on the market today, I truly believe that MLD’s no-frills, dogged focus on performance-to-weight matches my style of backpacking. I don’t need anything fancy to be comfortable and happy in the backcountry. Not that my tolerance for grodiness and plasticky fabric makes me better than anyone, but I do get a kick out of never changing my clothes.

And even though I prefer a closed footbox on my quilts, I like MLD’s plug design. It looks funky, but it works well and is a utilitarian solution that sums up the strengths of the Spirit. If you’re in the market for a synthetic quilt, then the MLD Spirit is certainly one to consider. It’s the epitome of ultralight done right, and performs exactly as promised.

Shop the MLD Spirit Quilt 38°

Similar Synthetic Quilts

Enlightened Equipment Revelation APEX 40°F
MSRP: $220
Temp rating: 40°F
Weight: 18.8 ounces
Insulation: Climashield APEX

Enlightened Equipment Enigma APEX 40°F
MSRP: $230
Temp rating: 40°F
Weight: 17.1 ounces
Insulation: Climashield APEX

Read our review of the Enigma APEX here.

Zenbivy Light Quilt 40° Synthetic
MSRP: $139
Temp rating: 40°F
Weight: 23 ounces
Insulation: 1d/3d polyester blend

Disclaimer: The MLD Spirit 38° was donated for the purpose of review.

Mountain Laurel Designs Spirit Quilt 38° Review - The Trek (2024)
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