PRIMA OUTDOOR – SLEEPING BAGS FROM GENUINE CZECH PRODUCER
How to choose sleeping bag
Before you start to browse through our unbeatably the most wide range of sleeping bags from the biggest producer in the Czech Republic, we will try to explain to you how to choose sleeping bag. However it is not possible (and it is not purpose of out web side) to copy technical literature or textbooks and make crash course of maths, physics, thermomechanics and other sciences and explain to you everything in detail, we tried to simplify this topic. If you are interested in more details, we are glad to receive your question by e-mail, call us or visit us personally in headquarters (where you can find also “shop” with complete assortment of PRIMA sleeping bags). Our employees will provide you all information and answer all questions that will help you to the right decision. If you are not satisfied with their answers, your questions will be sent to our or cooperative research workers (e.g. researchers in Technická univerzita in Liberec, textile faculty, Textilní zkušební ústav in Brno, etc.; or Swiss federal laboratories EMPA, development department of DuPont, etc.)
Team of PRIMA OUTDOOR, s.r.o.
History and theory
Eyewitnesses know that before 1989, decision was very easy. There were (if just were) only very heavy and huge so called “dekáèe” (quilt sleeping bags) and sometimes also so called “mumie” of the same qualities. If you succeed in getting feather (it did not exist in trade network), “unika” (it was only in one shop in the Czechoslovakia, there was waiting list – it took nine months to get it; and they sent it only cash on delivery and only in two colors: watery blue and watery red) and “monofil” (it was surprisingly commonly available) you could sew so called “péøák” (feather sleeping bag) at home – needless to say without zip. In so called “dekáè” you felt nearly all the time cold and in “péøák” you felt nearly all the time warm. Development of insulating materials and superficial clothes enregistered immense leap in last years. Nowadays there are so many types that it is not possible for amateur to know them a lot. And then, everyone presents that just his products are top class, the best and unbeatable. How to be well informed regarding insulating materials and superficial materials? There is not one ideal material. All materials have advantages and disadvantages.
Which sleeping bag is the right one?
Despite of scientific progress it is (and probably will not be) not possible to produce ideal universal sleeping bag. It would be perfectly permeable in hot days, air-proof when the wind is blowing, waterproof in rain and fantastically warm in bitter cold days. Of course it would be cheap, light and very small after rolling up. It is not possible to make this type of sleeping bag – and will not be. In summer you simply need different sleeping bag than in winter. Windproof quality (perchance waterproof) and permeability are opposing qualities, it means the higher windproof quality (perchance waterproof ) the lower permeability. And vice versa. The more permeable cloth is, the lower is able to prevent against wind and water.
It is certain that everyone who will not respect listed sequence when choosing sleeping bag will be dissatisfied.
The most important quality that we are interested in above all are temperatures which the sleeping bag is appropriate for.
Thermal insulating qualities of sleeping bag are defined by thermal insulating ability of insulating filling. It is in direct proportion to its specific thermal resistance and its amount. Thermal insulating filling criterion is amount of air molecules that it is able to attach. Others are only secondary qualities that can more or less decrease specific thermal resistance. So called “loft” (fluffiness – ability occupy as huge volume as possible, non-professionally, how much is sleeping bag able to blow up after being unpacked; way of sewing (sandwich, shingle), orientation of fibers in cloth etc – these are the important factors. The real insulating medium is not used filling, but air. Feather or synthetic material just make space that he should occupy. That is why you will fell cold in huge and heavy sleeping bag made of cheap, unbranded insulating material, but in thinner and lighter sleeping bag with quality filling (preferably branded hollow fibers) you will feel more warmly and in the smallest and lightest sleeping bag made of modern top class hollow fibers or microfibers you will feel the most warmly. In a simplified way, we can divide sleeping bags into four groups: ultra-summer, summer, three-seasonal and winter. If you often spend nights in open-air and during the whole year, it is ideal to have four types of sleeping bags. If you do not want to have so many sleeping bags, you have to make a compromise. For example this way: leave out ultra-summer one and in summer you will sometimes sweat. You have three of them. In accordance with principle “better warm than cold” you omit summer sleeping bag and from spring to autumn you will sleep in three-seasonal. Then you need just two types. And if you do not plan to sleep in freeze (when winter sleeping bag is the best one), good three-seasonal sleeping bag is sufficient.
Feather or synthetic materials?
Few years ago the only warm sleeping bag was sleeping bag made of feather. In recent years, synthetic materials win logically over feather that became exceptional material for top class sleeping bag for “dry” freeze in high-mountain areas where it does not rain and humidity is relatively low. Attention! Not in common high-mountain conditions, much less in arctic and Antarctic conditions! Because of high humidity, there is feather sleeping bag (however with the best outer cloths) something like ticket to hell! Feather absorbs humidity very easily – not only water when sleeping in puddle or in rain, but also air humidity. As we already know, humidity noticeably decreases thermal insulating qualities. Who did not see dumpish or even soaking feather sleeping bag, would not believe that feather practically disappears and instead of sleeping bag you have just wet cloth. In high freeze, you transfuse hailstones that were feather before. Then you dry soaking feather sleeping bag in dry conditions for one or two weeks – of it does not become mouldy.
The truth is that regarding parameters of compressibility and fluffiness, no synthetic material fully compares to dry and quality goosy feather.
Synthetic fillings
Advantage of synthetic material is in unassuming maintenance and in minimum humidity absorption. Sleeping bag with synthetic insulating filling is ideal for universal using from spring to autumn – always. And also as winter type except high-mountain dry conditions. Also whenever we do not want to burden with regular treatment and maintenance. Advantage is that it is possible to dry it easily and quickly and moistening does not overly degrade its qualities. This type of sleeping bag you can wash in washing machine for soft program without devaluation of insulating qualities as in case of feather sleeping bag. Synthetic fibers are the only solution for people with allergy to feather.
Name “hollow fibers” became wrong common for all synthetic fillings. Differences are usually abysmal. You can find many “no name” synthetic fillings, perchance with fictional and not registered brands (as Adi-das for CZK 30,- on markets from “mysterious” producers from the East). Its fibers are very fragile and that is why the cloth tears easily and decay, fibers are not hollow or contains little percentage of hollow fibers, fibers are made of inferior or recycled materials or linked with binding materials unfit for use. Its producers do not guarantee anything. In better instance, you will feel cold in temperatures that do not approach to temperatures declared by producer, in worst case there is a risk of dermal, respiration and other troubles, or for example total devastation of insulating cloth after first washing or after short period of use. Common feature is low price for that you can not buy neither standard cloth for sewing. Attention! Many Czech and foreign renowned companies have these types in their offer – however for higher prices (and then you can think that it is quality product).
Branded material have guaranteed quality and producers must respect many strict technical and health standards. Consider if you have so much money to buy cheap things.
Quality hollow fibers are several tens cm long and cut view shows one or more hollows (approximately of circular shape). Producers can use also spiral or shaped fibers to put more air into cloth.
Fibers are thermally processed into insulating fleece. Air molecules are not only between fibers (as in case of classic fibers) but also inside of fibers – that is why this fleece insulates better with the same weight.
The only branded fibers that were trustworthy until recently, produces supranational company DuPont and we alined them from the oldest and cheapest to newest and best: Hollofil 608, Hollofil II, Quallofil, Thermolite, Thermolite Active, Thermolite Plus and Thermolite Extra.
We can not mix up hollow fibers with microfibers. Its diameter is approximately ten times smaller than in case of hollow fibers. Its function theory: air molecules captured by microscopic structure of cloth should stick to its surface so the fibers do not lye on each other but on the air molecules. And the result is? Fleece should contain (with same weight and volume) more air and insulate better than the best hollow fibers. The best advantage of sleeping bags with this insulating material should be low weight and small volume. However disadvantage is its small resistance of very fine microfibers against mechanical expose, in comparison with hollow fibers, they quickly lost fluffiness and loss its insulating qualities. The well-known branded microfiber has trade name Thinsulate by supranational concern 3M or comparable Thermolite Micro by competitive concern DuPont.
Hollow fibers and microfibers have several advantages and disadvantages. Recently, concern DuPont developed three-part insulating fleece. It contains microfibers, hollow fibers and spiral fibers. This insulating material has trade name Thermolite Extreme and nowadays, it is the best insulation material in the world.
Recently, all of these insulations were surpassed by Polarguard materials. Gradually Polarguard was developed, then better Polarguard HV and finally the best you can buy today in the world: Polarguard 3D. This “magical” material is made of one infinite thermally linked crossed looped hollow fiber with triangle hollow and its diameter approaches to microfibers. It combines all advantages of hollow and spiral fibers and microfibers, keeps heat in the most challenging conditions and nowadays they have no competition. Usually, it is something for something: hollow fibers have good lifetime and worse insulation quality, microfibers vice versa. Polarguard 3D according to independent tests: it has the best insulation qualities and best lifetime. Miracles happen. Its outstanding qualities are: good compressibility and softness. There is also Polarguard ? (delta). In opinion of producer, it has of about 3 % higher insulating qualities than Polarguard 3D. Outer diameter of fiber is same as in case of Polarguard 3D, but triangle hollow is bigger. It should contain more air – but this way the wall of fiber became thicker. Its lifetime decrease in so far that when we measured insulating fleece or the sleeping bag, every time we measured worse results as in case of Polarguard 3D. Also response of users made persuades us that Polarguard 3D is the best insulating material for sleeping bags in the world.
Feather
is proven natural material with good compressibility and very good shape stability. Goosy feather is the most frequently used one. But… it is not feather like feather.
Eider duck feather is just dreamed insulating material. It is not used in practice – except one exception: on OUTDOOR fair (in Friedrichshafen, Germany) one Russian company offered wind-cheater made of eider duck feather. Amount of feather was not too high. And price? More than EUR 3,000, approximately CZK 100,000. My question how much should cost sleeping bag made of this material (where you need more of it) get a sincere laugh and no question.
Instead of goose feather, duck feather is often used. but it has lower fullness and after getting wet you can smell typical odor. Sometimes, goose feather is extended with duck feather.
Thermal insulating quality of feather is dependent on ratio of downy feather and small feathers. These are the numbers: 90/10, 80/20 etc. The first means that there is 90 % of downy feather and 10 % of small feathers. Another quality feature is so called “fullness”. It expresses total elasticity and expansibility – ability of feather to occupy certain volume. This quantity is measured in laboratories by internationally acknowledged method and it is denoted in cubic inches (cuin). Plain downy feather (100/0) has about 950 to 1,000 cuin, mixture 90/10 approximately 650 cuin and 70/30 has 500 cuin.
Attention. It is not practical to use plain downy feather; because small feathers increase mechanical resistance: so, the higher contain of downy feather (100 %), the higher is its fullness and fluffiness and the feather is warmer, but in the same time, it losses its fullness and fluffiness more quickly and it warms less. And if the weight very quality feather of sleeping bag is too low, it should be within several using. Then, feather is not able to fill the volume of chambers, there are gaps and there is a draft there – and then you have not too good summer sleeping bag. So, when buying you have to think if you want to conquer Everest and then you need extremely warm and light sleeping bag (that will be destroyed quickly) or sleeping bag not so warm but that you can use for several years without degradation of its qualities.
Finally: it is not possible to say that feather is antiquated material. The high-quality and the most expensive fillings approach just for sight to downy goose feather regarding weight and thermal insulation ratio. Who is going to stay in high dry freeze and must count each gram, he should choose quality feather sleeping bag.
After 15 years, PRIMA OUTDOOR, s.r.o. finished production of feather sleeping bags. Why? Because of development of synthetic materials, usage of feather as insulator is very specific and for tight group of users that several hundreds of these sleeping bags per year did not pay to us financially. Do not lose hope, only in Czech Republic, there are several companies that import and distribute feather sleeping bags.
Outer and inner cloth
Main requirement concerning inner cloth is permeability. Outer cloth of sleeping bag should at the same time (at least at some measure) prevent penetration of humidity into insulating filling. Sleeping bag as a whole should have sufficient permeability that allows humidity to go through to outer surface and spread out into the air. Average human sweat of about 0.5 to 1.5 l of wetness in form of water steams that have to go out. In opposite case, it capsules in the sleeping bag in to water and in the morning, you will be wet or sweat. If you sweat in relatively thin sleeping bag as well, it does not have to be very warm, but the outer cloth does not let out water steam. Damp insulating filling does not insulate as good as in dry conditions and thermally insulating abilities of sleeping bag get worse. Damp sweat skin, dress and inner cloth conduct warm away much better – and we want to prevent it.
Cloth should be as light as possible to allow the best expansibility of insulating filling. Inner cloth should be also pleasant to touch. Feather filling make maximum demands on used cloth. Cloth must be dense enough and downy feather and small feathers can not penetrate from chambers, but permeable enough so the water steams could go out. It is unrealizable task so you sometimes sweat in sleeping bag (do not change sweating with thermal comfort!) and other times feather goes through cloth. Membraned materials (e.g. Gore-tex, Gore Dry Loft, Excel Dry etc.) are used for feather sleeping bags. However, its price is “astronomical” and lifetime, let’s say, debatable. Do you know that Swiss army stopped to use dress made of Gore-tex and started to use cloths based on Tactel?
Very widespread materials are microfiber materials made of Meryl or Tactel that are used in case of feather sleeping bags and synthetic as well; and they are adequate combination of price and quality for rougher conditions. Classic 100% polyamid (so called nylon with water-repellent finishing) is the most usual material. Ripstop is strengthened variant of whatever cloth that is more resistant against scratch and tear. The cheapest sleeping bags have cotton inside. It is indeed pleasant to touch, but quite heavy, large, easy to soil, absorbs humidity and odors and it dries for a long time. If you insist on using of cotton, these sleeping bags are appropriate only for undemanding use in summer.
Construction
The simplest sleeping bags with synthetic filling have one quilted layer of insulation. It is not good idea for three-seasonal sleeping bag.
“Sandwich construction” with two or more independent layers. is the right solution.
“Shingle construction” is sometimes used – mutually crossing belts are sewn to outer and inner cloth and sleeping bag looks like there is more insulating filling that really is. It is called “false fluffiness”. Specific thermal resistance of sleeping bag is in direct proportion to amount of insulating material; and this type of sleeping bag is much more predisposed to mechanical damage of insulating fleece.
Temperatures
Czech Republic contracted an alliance with European Union. As we like it or not, one result is that we have to use European standards.
In literature you will find that there is no standard for using temperatures of sleeping bags. Maybe it is surprise for you that for many years, countries have own standards. Since 2002 European standard for sleeping bags has existed (exactly for measuring and counting temperatures). You can find its summary in special link.
Reliable producers or importers state these values. The slowest one state at least three values: max., comfort and extreme. If you do not find three values on sleeping bag but just one or two, it does not mean that the sleeping bag is bad. The author just tries to confuse the client. Then he can think that extreme temperature is comfort temperature… and extreme temperature absolutely is not temperature in which you should risk night spent in this sleeping bag.
Finally order? Do not triumph prematurely…
All given values are valid only in ideal laboratory conditions and for standard man or woman!
In practice, conditions of usage of sleeping bag can be extremely changeable. Every time it is combination of following factors:
- temperature of surrounding air,
- radiation temperature of surrounding air,
- speed and whirling of air,
- humidity captured in sleeping bag and surrounding humidity,
- dress of individual,
- position of individual in sleeping bag,
- insulation between sleeping bag and ground and thermal insulation of ground,
- squeezing of sleeping bag by weight and volume of its user,
- other than ideal surface and volume of user and space of sleeping bag ratio.
Physiological reactions that are determined by surrounding conditions and that determine discomfort and risk of hypothermia are very variable according to body temperature, hardiness, sex a etc. Each of us has different blood circulation, different metabolism and we sweat different amount of water during the night. These factors influence noticeably subjective feelings of cold or warm. In case of each individual, there can be changes during the time, e.g. because of fatigue, food, body situation, etc. They are influenced mainly by climatic conditions, quality of insulating underlay and physical condition, etc.
And finally – perception of cold is subjective!!!
Temperature using conditions are not quantities resulting from inner fundament of sleeping bag but it depends on using conditions, individual and its conditions in time of use.
So… everything is bad? Oh no, do not lose hope. It is not important to be specialist to know that sleeping bag that weights 1 kg and is specified for 30 °C below zero – that this sleeping bag is suspicious. Total amateur can after reading of this article approximately compare sleeping bags of different producers. The most important is type and weight of insulating material. When deciding between two types I recommend to choose the warmer one – especially for woman. One never knows when he will need temperature stand-by and if the sleeping bag has side zip, it is not necessary to be afraid of excessive warm. And some extra grams (however they become heavy during the day) will get back in form of sleep through night. Dispensation of energy during the night in sleeping bag when you feel cold is every time higher than dispensation of energy when you carry extra half a kilogram. No kidding.
Simple instruction based on this chapter:
EVERY TIME choose sleeping bag with sufficient insulating reserve. Data on tag do not mean that you will feel comfortably in any conditions but only in ideal laboratory conditions that you will not meet in practice. And which reserve you should choose? It depends only on you and conditions you could experience.
PRIMA OUTDOOR, s.r.o. tries to help you that way that it state in its sheet s also recommended using of sleeping bag (apart from temperature range) in different seasons (it is expressed by number of dots for each season as ideal, very good, good and unsuitable). If you wait for exact advice regarding temperatures, then we recommend to have at least 10 degrees as reserve but if you are woman or child or older man, if you are not in the best condition etc – you should have 20 degrees and more.
It means that temperature range of sleeping bag is just directory value that comes out of thermal insulation measurement of sleeping bag and analysis of this measurement regarding temperature usage that helps compare types of insulating materials and sleeping bags – in standardized conditions.
Size
Right size is very important. Small body will not “heat” excessively large sleeping bag and vice versa – too small sleeping bag (that will not allow comfort stretch of body) compresses insulating layer that insulates less.
Sleeping bag should be moderately loose so the sleeper when turning does not turn with the sleeping bag but just himself. Producers of sleeping bags usually have two sizes regarding height of figure.
PRIMA OUTDOOR, s.r.o. has all types of sleeping bags in two sizes. We offer more – we are able to sew whatsoever type of sleeping bag – wider or thinner, longer or shorter or tailored sleeping bag.
Collar
Inner collar should not be absent on every satisfactory sleeping bag that after fastening divide sleeping bag into two parts – space for head and body. Exhaled water steams increase humidity of insulating fleece, air molecules are replaced by water molecules and insulating ability decreases. Who is accustomed to mist with breath his sleeping bag, he does not make a good thing. Only approximately 10 % of whole amount of heat that your body makes go away in form of breath. Change of insulating abilities of sleeping bag that is moist or dry in case of synthetic insulating materials is about several tens and in case of feather sleeping bags about 100 %.
All PRIMA sleeping bags certainly have collar.
Zip
Today, sleeping bags without zip are not produced. However, zip and zip is not the same. In case of unbranded zip you risk that it will betray you in the moment when you need it less. Frosty night – spent in sleeping bag used as blanket because you can not fasten it, it breaks out or slider came off – can be your last night. Zips YKK are absolute world top class, Czech zips Ws20 are also very good.
Zips YKK that uses PRIMA OUTDOOR, s.r.o. are self-locking. It means that zip does not spontaneously open, slider stays all the time in the position you want to – totally opened or totally zipped up.
Zip should be covered with inner belt that prevents escaping of heat through zip. All types of PRIMA sleeping bags have zip covered with belt.
Warm seams
We should not find so called “cold seams” neither in case of simple sleeping bags, it means sewing through whole sleeping bag. If you elevate opened sleeping bag against light and you can see gaps after needle through and through, get rid of this type of sleeping bag.
You can not find “cold seams” in case if PRIMA sleeping bags.
Compression cover
Compression cover is marketing trick of producers in last years. Sleeping bag rolled up in compression cover with printmaking and needlework looks better and tempts to buy. It says nothing about quality of sleeping bag inside.
Yes, compression cover allows compress volume of sleeping bag to 40 % of original volume but each of this compressions lower lifetime of insulating material – synthetic and features as well. Fluffiness imperceptibly descends and sleeping bag after unrolling blows up less. And the longer and often the sleeping bag is compressed, the worse.
Compression cover is part of all PRIMA sleeping bags. Use it with reason, it means in case of necessity and only for transfer.
Right storage
For most of us, sleeping is not insignificant investment. There are general rules how to take care of sleeping bag so it lasts for a long time.
Insulating underlay
Do not forget that you will feel cold even in the most warm sleeping bag, if you do not have quality insulating underlay – groundcloth! Most of people do not pay attention to groundcloth and if they feel cold at night, they blame sleeping bag. They do not know that because of inferior underlay 2/3 of warm (that your body produces in sleeping bag) can leak from sleeping bag through underlay!!! It is not a babble, it is result of measurement of Swiss federal laboratories EMPA!!! Renowned world producers measure its sleeping bags and since 2003 PRIMA OUTDOOR, s.r.o., too. Realize that sleeping bag is compressed in surface which you are laying on into zero and in this place it does not insulate. More you have direct contact with ground that is often more cold than air. Inflatable and self-inflatable underlay is the best, or you can use quality groundclothes made of foam material. The more thick, the better. Do not save at incorrect place and when you have quality sleeping bag, do not mess it up with groundcloth.
SO… LET’S GO TO CHOOSE THE BEST!
PRIMA OUTDOOR, s.r.o., Merhautova 236, 613 00 Brno, Tel./Fax.: +420 548 212 768, Mobil: +420 608 963 388, E-mail: prima@prima-spacaky.cz