Underquilt vs Top Quilt: Which One Do You Need?

Sleeping in a hammock in the cold requires preparation. If you just have your hammock in weather colder than 65 degrees, you’re going to be cold!

What’s more important for staying warm while hammocking? An underquilt? Or a topquilt? An underquilt acts like a tiny cave that traps your heat so it can radiate back to you. Because of this, an underquilt is more important for staying warm and should be the priority. Many kinds of blankets or sleeping bags can function as a topquilt as necessary.

Does this mean you shouldn’t think about a top quilt at all? Well, there’s more to it. As I was doing research on the subject, I found some other compelling reasons that might impact your insulation requirements. Read on to make a fully informed decision.

By the way, as an Amazon Associate, I earn when buying qualified products through links on my site.

Definitions of Underquilt and Topquilts

Before moving on, let’s be clear we are all understanding what we’re talking about.

What Is An Underquilt?

An underquilt is a layer of fabric that often resembles sleeping bag material that hangs underneath your hammock, between you and the ground. You do not hang in the underquilt, as one of the main purposes of this is to add an air gap for additional insulation. The underquilt adds insulation which prevents wind from stealing your heat.

An underquilt in action: chas S on Flickrlicense — Some cropping and color changes made

Underquilts come in many different designs, but they are often intended to cover the entire length of your hammock. Some underquilts even zip up and over the entire hammock with some ventilation to make a pod.

What Is A Topquilt?

A topquilt is in essence, a blanket. Many topquilts resemble sleeping bag material, but they do not wrap around your entire body like a sleeping bag. Many topquilts feature a footbox where your feet are almost completely enclosed, but the rest of the topquilt is open on the back.

One of the benefits of a topquilt is that you are carrying less weight. The argument of why you would use a topquilt instead of a sleeping bag is that because sleeping bag insulation is compressed when you are laying on it, you lose the benefit of the insulation anyway. With a top quilt, you are resting directly on your bottom insulation (like your sleeping pad).

Why You Should Choose an Underquilt Over a Topquilt

An underquilt is the de-facto solution for staying warm while sleeping in a hammock. As I was poring through many different forums and watching different Youtube videos, that seems to be the consensus among most other hammockers. You should prioritize getting an underquilt before a topquilt. Here are some reasons why:

1. Keeping Your Bottom Warm is Everything

Unfortunately, the best way to understand this is to try sleeping in a hammock with a good sleeping bag and blanket, and waking up in the middle of the night with the dreaded CBS (Cold-Butt Syndrome). No, I did not make up this term.

If there was no such thing as wind, then CBS wouldn’t be as much of an issue. But because of wind, since your hammock is not really insulation at all, wind whips underneath your hammock and takes away that hard-earned heat that your body is making.

It’s similar to the concept of blowing over a hot drink (as opposed to blowing INTO a hot drink). High pressure is always trying to go to low pressure, so you can cool down your hot drink faster if you blow over the top of your drink. When you displace the hot air, more heat tries to displace it.

So, as you’re hanging in a hammock, you’re like a cup of hot chocolate, and the wind is blowing over your backside, stealing your heat faster than you can say CBS.

Because of the design and shape of a hammock, the top side of the hammock has a depression that you lie in, the sides of the hammock actually do stop the wind a little bit. While having a blanket or sheet of some sort is also important, your bottom side will leak out more heat. And happiness.

An underquilt stops CBS in its tracks by trapping the air underneath your body, thus creating insulation and saving happiness.

Say no to CBS

2. Hammocks and Comfort With an Underquilt

So, underquilts are great at keeping you warm, but what other reasons are there over a topquilt or a sleeping bag?

One of the best parts of a hammock that make it a favorite for many people is that hammocks are incredibly comfortable. I can attest to this, myself. More than the comfort factor and the fact that you’re not laying on the hard ground, there is something about being suspended in the air.

I’m not sure if it goes back to the comfortable feeling when we were in the womb, but there really is an instant relaxation that I experience when I climb into a hammock. I don’t really have any science to explain this phenomenon, but I’ll just call it the Ahh-Finally-I-am-in-a-Hammock-Sensation. Or, AFIHS if you’d like.

AFIHS, (comfort) can be inhibited by a sleeping bag. From personal experience, even though I love hammocks, twisting around in a sleeping bag to get the sleeping bag to line up just right is kind of a pain in the CB. (cold butt). A lighter blanket is much preferable if you can get away with it so you don’t have to deal with scooting around in your hammock for 15 minutes before you can find the right alignment.

This is another reason why a nice underquilt is preferable than a top quilt because you can appreciate the warmth of the underquilt without having the same bulk of a heavy top-quilt or sleeping bag, and in many cases you can get away with a lighter blanket (some people even sleep with blankets as light as a sheet when using an underquilt!)

3. Versatile for Many Seasons

Underquilts are designed to hang underneath your hammock in such a way as to capture heat from your body, but where you attach it is completely up to you! In fact, some actually choose to adjust their underquilt in such a way as to not cover the entire hammock, thus creating a partial heat pocket. This works well for summerish months where it gets under 65 degrees Fahrenheit but is still too warm for the whole sleep system.

Also, as mentioned before, you can use a very light blanket in warmer weather with an underquilt and be hanging at a cozy temperature. But, if it gets colder, you can bring out the sleeping bag, blanket, or topquilt if you have one to combat the cold.

With a topquilt, you can poke out a leg or an arm, but if it’s in that in-between stage, you might find yourself in that uncomfortable position of being too hot and too cold.

A Couple Reasons Why You Might Want to Get a Topquilt Instead

So, why on earth after those very compelling reasons would you not get an underquilt?

Price of Underquilts

Two words, Mun, and Ee. To be frank, high-quality underquilts are expensive. When buying a hammock sleep system, your underquilt may be the most expensive part if you get a premium underquilt. Thankfully, there is a huge payoff, to be sure, but if you’re wanting to get enough insulation to be able to sleep comfortably, you can definitely make it work with a sleeping pad and a top quilt.

Also, fortunately, underquilts are getting much more common, and the price is coming down significantly for 3-season underquilts. When it comes to insulation, though, there is a correlation between price and warmth, so take that into consideration. Also, as is usual with camping gear, the cheaper the gear, the heavier it is more likely to be.

You Already Have a Nice Topquilt

If you already have a nice top quilt rated for low temperatures, you absolutely can get by if you buy a sleeping pad to go with your topquilt. I have a coworker that has slept in around 45-degree weather with a sleeping pad and he had never heard of an underquilt until I’d asked him what he used. He does actually relocate some dead brush to create a windscreen, though.

Less Gear = Less Fuss

If you’re trying to make a hammock sleep system that’s simple, it’s totally understandable if you want to stick with what is strictly straightforward. Any sleep system takes practice, as does anything regarding hammocks. It is arguable that using an underquilt is more complicated than using a topquilt alone or a sleeping bag, and that’s fair. If you’re not planning on hanging in colder temperatures, then you may not need to invest the time to figure out how to use an underquilt.

If you are fortunate to live somewhere with two trees in your backyard, then you can use this amazing opportunity to see what your needs are. Try sleeping with just your topquilt or sleeping bag or whatever you have. If you try and cover up with multiple blankets from your house and you are still cold, then you might consider trying an underquilt.

Sleeping Pad vs. Underquilt

This is a huge subject that deserves its own attention. Because of this, we wrote an article addressing this subject at length that you can find here. There are lots of things to consider including weight, cost, warmth, setup time, comfort, etc, but I’ll summarize a couple of things here.

Insulation of Sleeping Pads and Underquilts

Underquilts are, at least in the hammocking community, considered superior in insulation because of the air gap and wind-blocking advantages of the underquilt. That’s not to say that a cheap underquilt will beat out an insulated high-quality sleeping pad, you have to look at the temperature ratings and the reviews of each if you want to find out for sure.

To that point, some sleeping pads are insulated. If you get a sleeping pad that wraps around you and is insulated, then you may be competing very closely to the warmth you can get with an underquilt.

The Case of the Wandering Sleeping Pad

Everything I said about scooting around while you’re in a hammock can be escalated to the next level when you add sleeping pads into the mix. Sleeping pads in a tent have a tendency to meander–sleeping pads in a hammock downright run away from you.

I can attest to this. I’ve tried to sleep with those cheap blue foam sleeping pads in a hammock, and it does work, but if you move around when you sleep, you might as well go jump in the cold lake water right now so you can acclimate yourself for that cold night. (just kidding, don’t jump in cold lake water.)

Wandering sleeping pads are not a deal-breaker, though. You can just be a little bit better prepared than I was. Some sleeping pads are so large and are designed to fit a hammock so well, that they actually surround your upper torso so that you don’t get roll off of them. If you are going to purchase a sleeping pad instead of an underquilt, take some time to find a sleeping pad that will be ideal for hammocks rather than getting the first sleeping pad you find at Walmart.

Sleeping Pads Are Simpler to Setup Than Underquilts

Putting a sleeping pad in a hammock isn’t usually done successfully the first try–it does take some practice, but it is definitely easier than setting up an underquilt. Since a sleeping pad can provide all the insulation you need for many conditions, this works just fine for many people.

Examples of Hammock-Specific Sleeping Pads

Klymit makes a hammock-specific sleeping pad that is meant to wrap around you and give you wide insulation. I use a Klymit sleeping pad for sleeping on the ground, and they share the same multi-air chamber design, and they are good quality sleeping pads. They come in insulated and non-insulated versions depending on your needs–you can check it out on Amazon here if you’d like.

Make your sleeping pad work. If you have an existing sleeping pad, you can make this work by putting the pad in and steadying the pad with your hands, carefully, as you sit in your hammock.

DIY insulation Some people have tried using Mylar (the material emergency blankets are made of) or Reflectix with success. An issue with this method is that … well, Mylar is known for its heat retention, but not for its comfort. If you layer a blanket on top of the Mylar, you can increase the comfort level and keep the insulation.

What Temperature Rating Should I Get For an Underquilt?

This is always a tricky question to answer since the temperature ratings are not applied consistently. Every company has a different interpretation, and furthermore, you might think about what is too hot for one person to be freezing!

Remember, that temperature ratings are not where you will be comfortable, but where you can survive. Furthermore, it’s a bit more complicated with underquilts since they are assuming that you have some other cover beside the underquilt. If it was 20 degrees out and you have a 20 degree underquilt with nothing else–well, that will be a very unhappy night. Underquilt temperature ratings coincide with adequate top blanket protection.

If you’re not planning on camping in frigid conditions (colder than 40 degrees), then a 3-season underquilt will likely suit your needs. I can’t understand the importance of trying your sleep system with a trial run to make sure you can sleep comfortably through a cold night while you’re camping.

If you’re camping in sub 40-degree weather, you should make an effort to get a 4-season underquilt.


Peter is a software developer who loves to take every opportunity to go outside that he can get. Peter grew up going on long backpacking excursions with his family every Summer and now enjoys staying at the beautiful Texas State Parks and swimming in the amazing Texas Rivers.

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