Sleeping bags and quilts can provide light-weight and compact insulation for a good nights sleep. I have found that you get what you pay for when it comes to sleeping bags and quilts. It’s also important to have insulation and comfortable surface to sleep on top of (pads for most, hammock users also use under-quilts).
I use a Ghost Blanket made in 2001 by Nunatak, one of the first companies to make a backpacking oriented down quilt. This quilt weights a mere 16 oz and is rated for use to 32F. Today, I would most likely purchase an Enlightened Equipment Revelation quilt. In warm weather I lay the quilt loosely over my body. As the temperature drops I tighten the straps on the quilt to block drafts, and add clothing as needed. I am comfortable using this quilt down to 30F when wearing a fleece hat, a light weight base layer, and wool socks. In colder weather I have been comfortable by adding a down balaclava, insulated clothing, insulated socks, and enclosing the quilt in a MLD SuperLite bivy which has me comfortable to 10F. When I have all my clothing on and am still chilled I make myself as small as I can and pull my head under the quilt with only my mouth sticking out. In the past I would switch to a Western Mountaineering Versalite when I expected expected cold temperatures below 15F. My wife and I share an Enlightened Equipment Accomplice Quilt when backpacking together.
Amount of Insulation
There are a variety of factors which should be considered when selecting a how much insulation you want. First you need to figure out what the lowest temperature you expect to face is. Next you should consider if you are a “warm” sleeper or a “cold” sleeper. For example, the WM VersaLite keeps me very comfortable to 0F while I am wearing just my Cap4 base layer and my wife though was perfect at 35F while wearing clothing, fleece, down vest and warm hat! In addition to clothing, solid tents or bivy keep you approx 5-15F degrees warmer than the outside, and typical liners can add 4-10F. For other factors (and tricks) to stay warm, check out my getting a good night of sleep post.
Dry, insulating clothing will boast the warmth of your sleeping system. Damp clothing can sap your warmth, which is why some people say sleep naked. Just remember that the amount of insulation you need when active is much less than when you are sleeping. See my notes on insulating clothing for more information.
Around 2006 most companies started using the European rating system EN 13537 to describe the temperature comfort range of their sleeping bags. While an improvement over no standard at all, there have been a number of studies which have demonstrated there can be significant testing variance. I had hoped that this would get resolves by now, but it still seems to be an issue.
There are several high quality companies such as Western Mountaineering use their own standards for temperature rating based on real world testing by the manufacturer and by customer reports. In most cases, the company’s “rating” is more conservative than EN 13537 testing results. For example EN 13537 testing result might be 0F, Western Mountaineering might list the bag as appropriate for 20F.
According to testing done by the US army, the average person needs the listed loft to sleeping well. I have added an additional column which is the amount of loft on the top side of a Western Mountaineering bag for the specified temperature rating. Nearly everyone agrees that Western Mountaineering bags are accurate (for people who sleep cold) and conservatively (for people who sleep warm).
|Effective Temp||Army||Western Mountaineering|
|+40F||1.5″||1.5″ (3″ total)|
|0F||2.5″||3.5″ (7″ total)|
|-20F||3.0″||4.25″ (8.5″ total)|
|-40F||3.5″||5″ (10″ total)|
Bottom line, no standard can tell you exactly how much insulation you will need. Use rates as a starting point, take a thermometer on trips to record your experience. As time goes on you can figure out the amount of offset you need compared to the warmth rating.
Type of Insulation
I believe down is in most cases the best insulation material for sleeping bags and quilts. When sleeping in temperatures below 50F, down will be lighter weight and more compactly packed than any other insulation. If properly cared for, down can last for five times longer than synthetic insulation which tends to break down as it is compressed. So while synthetic is cheaper at the time of acquisition, down can be cheaper over the long term. I recommend looking for ethically sourced down which is at last 700 fill power.
The biggest concern with down is how moisture would effect performance. I was very concerned about this when I started backpacking, and selected sleeping bags using synthetic insulation. In 2001 I decided that I was being driven by fear and switch to down insulation. I came to recognized moisture came from two sources. The first is my perspiration. In warm conditions this isn’t a big deal, but when facing consistent, sub-freezing conditions this can result in your perspiration getting frozen in the insulation before it escapes. The simple solution for this is to use a vapor barrier. The second is the insulation getting wet from external sources. This can be addressed by carrying your sleep gear in some sort of waterproof bag, and only taking it out of the bag when in a space which is dry. Since I switch to using a down quilt I have very rarely gotten the quilt wet. When I have (using a tarp which was too small) the down didn’t get sufficiently wet to impact performance, and I was about to dry it a day later when the sun came out long enough to dry.
When you can’t protect the bag / quilt from moisture would be when using synthetic insulation. The big advantage of synthetic insulation isn’t so much “it’s warm while wet” but that it absorbed less water and is much easier to dry in the field. It is virtually impossible to keep an issulating item dry when it is used as a garment while active and as insulation for sleeping such as the classic poncho liner, sometimes referred to as a woobie. The good news is that if you only need modest amounts of insulation, that synthetic ended up being about the same weight as the same item made from down because more fabric is required in the down garment.
For more details, I have a post about insulation materials.
Insulation filled blankets and specially design quilts with foot pockets have become increasingly popular with backpackers. Many have noted that quilts are cheaper and warmer / weight than more traditional sleeping bags. A quilt doesn’t need a zipper. A quilt is variable girth so you can wear all your clothing for added insulation under the quilt without compressing your insulation. In 2002 quilt had a significant warmth / weight advantage over most commercially made sleeping bags. Today quilts still have an advantage, but the gap is smaller than it used to be due to improved designs and materials used by many manufacturers.
Sleeping bags are the most common way people stay warm in the back country. Sleeping bags come in a variety of shapes and styles. Most common among backpackers is the so call mummy bag. Mummy style bags are popular because the they minimize weight by having little wasted material and by providing a good seal around the head and shoulders to prevent heat from leaking out. Mummy bags typically list the shoulder girth which varies from 55″-70″. I have found that 62″ is the best for me as a 160lb 5’10” male. Ideally there should have enough room to allow you to move as much as you need to be comfortable, but no more than necessary to minimize how much space you need to heat up and to minimize convection.
Top-bags are a cross between a quilt and a traditional sleeping bag. They have a sleep bag design combined with a fabric bottoms which holds a sleeping pad which provides insulation. The theory is that you are going to crush any insulation which is under you, so why carry it around with you. An advantage of the top bag over quilts is they cut out any chance of drafts coming in through the sides.
Rectangular bags are popular with some because they can be converted to a blanket or rectangular quilt and they provide a lot of room to move around.
Half bags, sometimes called elephant foot bags such as the Nunatak Akula were popularized by climbers. These looking like sleeping bags, but only cover the legs and are used in conjunction with an ultra warm jacket and hood to keep their upper body warm. Most backpacking find this system requires an insulating jacket which is too warm for normal use. Another “innovation” which hasn’t seemed to survive were sleeping bags with integrated arms which could be “worn”. Example of this were the now discontinued Lippiselk Bag, Exped Wallcreeper, and Nunatak Raku.
Two or Three Season?
As noted above there are a variety factors which can effect what sort of sleeping bag you might select. In most cases I would recommend against getting the warmest sleeping bag you can find since in most conditions you will be carrying unnecessary weight and you run the risk of overheating at night.
I believe most people will be best served by getting a light-weight mummy bag or quilt which will keep them warm enough down to 20-30 F. This will keep you comfortable in the conditions most people face on “3 season” outings and can be boasted with clothing or a liner. If you are regularly facing conditions below 10F, I would recommend having a winter bag or using an over-bag. Another approach for people are sleep outdoors in all four seasons is to use a summer weight bag which is appropriate for temperatures down to say 40F, and then use a warmer bag for the rest of the year.
Recommended Bags and Quilts
While I track general trends in the sleeping bag and quilt market, I haven’t been keeping close track of all the various models. Cleverhiker’a best sleeping bags matches my sensibilities and is more up-to-date than a page I might maintain.
There are a few things I would either emphasis or add to their observations. First, Western Mountaineering makes amazingly high quality bags which are really “dialed in”. Feathered Friends continues to make excellent bags. Some of the best quilts made by Enlightened Equipment, Nunatakusa, Katabatic Gear. Hammock Gear is one of the best values. There is an extensive spreadsheet of quilts.
Second, I would recommend selecting a quilt that can lay fully flat by the feet. Some quilts have a foot pocket which is sewn close. While this can save weight while insuring good performance in colder conditions, it makes the quilt much less comfortable in warmer conditions when you might want some cooling drafts.
Hints for Quilt Users
When using a quilt it’s important to have a warm hat since typically your head will be outside the quilt. In colder conditions, I would recommend a high loft balaclava. It may be possible to drape a quilt over your head. On several shorter trips when it was surprisingly cold I pulled my head under the quilt which gave a boast in how warm I felt. On a longer trip I would have worried about the moisture from my breath condensing in the insulation… but so far this hasn’t been a problem I have experienced.
Some people think quilts are inappropriate in colder conditions because movement can cause drafts and the colder it gets, the more the drafts will impact comfort. First, let me say that psychologically, there is something really nice about snuggling down into a warm, puffy sleeping bag which a quilt just doesn’t match… but I have found quilts work fine in colder conditions. First, a shelter system which blocks the wind (double walled tent, bivy, etc) can provide protection from winds. Additionally, quilt users are typically wearing high loft clothing as part of their sleep system which provides a second barrier against drafts. Furthermore, a quilt + clothing strategy typically results in an easier transition because you are already in warm clothing. Finally, quilts are simple, so they use less material, are less likely to fail.
There are some downsides of a quilt. First, they are more prone to drafts than a typical sleeping bag. So a sleeping bag will be warmer for weight when used by an extremely restless sleeper, especially if using a tarp in wind.
A possible downside with using a quilt is that you will be sleeping directly on a pad, which typically isn’t breathable. Some people find this unpleasant. Some people say you can’t be a side sleeper with a quilt. I haven’t had a significant problem. If you are doing this without a bivy you might sometimes run into insect problems. On one trip I was mobbed by ants. I could have mostly sealed a sleeping bag off, but there was not protection with the quilt. Confused yet? If not, you can look at a long thread arguing about quilts -vs- sleeping bags.
Couples often want to be able to sleep together. If a couple sleep close together, say spooned, they should be comfortable in temperatures which are 10-15F colder than they would be comfortable in under the same insulation without someone else. I think the best solution is a down or high loft synthetic quilt which is large enough to drape well over two people such as the original Nunatak backcountry blanket or the current Enlightened Equipment Accomplice double quilt. You can also use a rectangular sleeping bag zipped open like Western Mountaineering’s MityLite. The most common approach is to have two sleeping bags which use the same zipper, with one bag having a left zip, and the other bag having a right zip. Personally, I have been less than happy with the sleeping bags zipped together. Zipping sleeping bags together often does not give this warmth advantage because the combination of the two bags has a tendency to billow a bit pushing warm air out. Additionally, they didn’t seal very well around the face and neck. If you place a high loft jacket around the opening that it can help the sealing problem but this has never been satisfactory for me.
Suggestions of Winter Insulation
In extreme cold, it is almost a given that the dew point for your night-time perspiration will be somewhere inside your sleeping bag since there is a large temperature gradient being warm on the inside and below freeze at the shell. As a result your insulation will accumulate moisture. Down bags are fine for many days but then you will find their performance dropping as they lose loft. Synthetics bags are better a maintaining loft as the accumulate moisture from condensation, but they to will also lose loft over time. Typically the most effective solution to this problem is to use a vapor barrier. A vapor barrier is a waterproof layer which is placed between your body and your insulation which prevents you perspiration from entering your insulation and helps keep your skin moist. Your skin wants to be in approx 78% humidity and will perspiration to try and retain this. You can use specially designed liner bags, wear vapor barrier clothing, or use a sleeping bag such as those from WarmLite which has an integrated vapor barrier. Since you are protecting your bag from internal moisture, I would recommend using a highly protective external shell made from eVENT or DryLoft because you want maximum protection for your insulation and the vapor barrier will protect the insulation from condensation. You could also consider using an overbag, or an insulated liner combined with whatever you use in milder conditions. There have been several threads at BPL about combining sleeping bags and/or quilts for colder conditions. I would also note there are a number of winter techniques which will help you be safe and comfortable.
I don’t have young kids anymore so I am not on top of the best options. Most kids bags weren’t particularly great. Several companies will make custom length quilts, but these will be expensive and the kids will outgrow them. We tried several kids bags and eventually settled on a Montbell Super Stretch bags which had a drawstring that let you shorten the bag in the field. When my son was young he used the shortened bag, and now it’s used in it’s full length configuration. Alas, this feature no longer seem to be present.
I have completely lost track of the best budget sleeping bags. Years ago the Kelty Cosmic line of Down Mummy bags have been the recent price champs. These bags were optimistic in their ratings, but were well work the money.