Tag Info

Hot answers tagged

14

It's probably worth pointing out that a lot of people reading this question may be thinking along the (commonly quoted) line that about 80% of body heat is lost through the head - which is much more of a myth than people realise (See here for details.) From what I remember, it was an experiment done with people fully kitted out apart from the fact that they ...


13

Heat loss can occur from anywhere on the body through a number of processes: Conduction e.g. when sitting on the ground. Convection e.g. due to wind chill. Radiation i.e. heat loss direct to the environment from exposed skin. Evaporation i.e. heat loss through perspiration. Other factors: Metabolism generates heat; conversely, without enough sustenance ...


12

From experience I can tell you that lying on rock is the most effective way to become cold over night. Bare Earth Has at least some air gaps in the soil, which insulate (not too much). If there is any soil, the vegetation and roots provide some insulation. Does not reach as cold a temperature as rock, 24" below the surface is a consistent 40-50 degrees ...


8

My original answer to this question sparked a surprisingly intense debate, so I'm rewriting it to clarify a few points and offer a more holistic answer. Let me start by saying that every square inch of skin on the human body is capable of allowing heat to escape. That is to say, if you wear a jacket with no pants, your legs will lose more heat than your ...


4

here is a pictorial answer to try and figure this out! I believe this is a un-clothed male under a thermal camera (SFW)


3

Down is actually a pretty durable insulation, and if it is properly cared for will last much longer than any synthetic insulation. Some people use the same down sleeping bag for decades, but there are a lot of variables at play, and maintaining a down sleeping bag is a bit of an art form. When you buy a used down sleeping bag you will want to know: How ...


3

In my opinion two layers with say 60g/m² and 100g/m² are better than one with 160g/m². The different distribution of isolation is a point but I don't think this is relevant. You can get jackets with all kinds of stuffed torsos/arms/backs/arm-pits in lots thicknesses. The big advantage of the layering besides the versatility is the caught air between the ...


3

Leaves under your tent will offer almost no value as you will crush them when you lay in your tent. The primary benefit from leaves comes from dead air space. However they will provide a more smooth and soft sleeping surface. Leaves piled around your tent will provide good insulation as long as they do not get wet. I could not find an R value, but I did ...


2

When I have to sleep in moist cold air I always put some newspapers under my matras. It absorbs the water thus keeping me much better dry and warm. If those leaves are dry when find them you can also put them under your matras with the same effect. I think it will work even better than putting them under the tent.


2

This is almost certainly close to the R-value for a "dead air" space the same thickness as the leaf layer and the less compressed the leaves are the higher the R-value. Setting up a test for this using a heat source and one or more thermometers shouldn't be too difficult.


2

When we get cold vasoconstriction occurs. This prevents the blood at the extremities being subject to heat conduction away from the body. This is not an adaption, this is a reaction. The body emits heat all the time because the body working and but wants to remain at constant temperature. If the ambient temperature is such that we can lose this heat, we ...


2

Yes, you can always add layers to stay warmer. Exactly how much warmer isn't really possible to figure out, as different jackets put their insulation in different places (e.g., more in the torso/arms/hood). Using multiple layers has the benefit that you can take off only some of your insulation if you are getting too warm (for example, if you start hiking ...


2

Fill power doesn't measure crush resistance. It measures the inverse of density, in units of cubic centimeters per gram or cubic inches per ounce. Insulation doesn't depend on fill power. Insulation simply depends on thickness. However, a higher fill power allows you to achieve a greater thickness while carrying a given weight on your back. Fill power is ...


1

You would normally dress for the activity you're about to preform, and then add a watertight layer on top of your other layers. You also have to be certain that while the wet can't get to you from the outside, your poncho won't protect you against your on perspiration. As to address your direct question, you should insulate your head to protect against the ...


1

The primary advantage of higher fill power down is that it is warmer per ounce (or gram, if that's your thing) than down of a lower fill power. If you had two nearly identical sleeping bags: same shell material, same weight of down, but one had 850 fill power down and the other had 700, the 850 fill power would be about 3˚F warmer. More insight into this ...


1

Lots of ways to reduce heat loss: Wear a hat scarf and gloves as these keep the most important parts of your body warm. Wear warm knickers (even if you're a guy). You can get fleecy knickers but not fleecy pants. Also, you can huddle, like penguins as it reduces your surface area and conserves bodyheat.


1

The main problem with any ratings is that the insulation degrades pretty quickly, at least the synthetic one. Down holds its insulation properties longer, but it’s not perfect either. So the only reliable way to find out the quality of an older bag is spending a night in it.


1

The primary rating that should be on the bag is the pounds of insulation. It is a somewhat imperfect measure, but a summer bag might well be 2 or 2.5 pounds. A three-season might be 4, but that would not likely be enough for actual outdoor winter camping - but OK for a semi-heated cabin space. An older full-winter bag might be six pounds or more, with ...



Only top voted, non community-wiki answers of a minimum length are eligible