Confused or TQ+UQ temperature ratings... Please help.

[hangingbooger20]

I am looking to replace my sleeping pad with an underquilt and I am a little confused about uq temperature ratings and the rating of a combined tq + uq system.

Here is the expectation that I need qualified...

1. If I have just a 20* underquilt and hammock (with tarp over) will I be warm in 20* weather?
2. If I have a 40* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 20* weather?
3. If I have a 20* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 0* weather?

Let's assume that I will be wearing micro fleece top and bottoms and wool socks and that I am a warm sleeper.

Also assume that my gear is of a high quality... Zpacks 20* bag... Hammock gear or equivalent underquilt...

Please feel free to riff off of these questions and throw me some science...

I am looking for your opinion and the truth... Please help!

Thank you

[Pvt.Donut]

If you are a warm sleeper, a 20° quilt set should keep you warm at 20°. The general rule is to give yourself a 10° buffer but you could supplement warmth by wearing more clothes to bed. Will that set up keep you warm at 0°? Probably not. Fleece top and bottoms with wool socks will help but I imagine it would only add like 5° of warmth. Having only a 20° UQ and no top quilt would probably only keep you warm down to like 70°, seeing as heat rises there is nothing trapping your body heat near your body.

[TrailSlug]

I am looking to replace my sleeping pad with an underquilt and I am a little confused about uq temperature ratings and the rating of a combined tq + uq system.

Here is the expectation that I need qualified...

1. If I have just a 20* underquilt and hammock (with tarp over) will I be warm in 20* weather?
2. If I have a 40* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 20* weather?
3. If I have a 20* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 0* weather?

Let's assume that I will be wearing micro fleece top and bottoms and wool socks and that I am a warm sleeper.

Also assume that my gear is of a high quality... Zpacks 20* bag... Hammock gear or equivalent underquilt...

Please feel free to riff off of these questions and throw me some science...

I am looking for your opinion and the truth... Please help!

Thank you

Remember that a top quilt is only half of the combination and the bottom quilt is the second half of the combination. So in the simplest terms to stay warm at 20° you need a 20° top quilt and a 20° bottom quilt. A top quilt is like the top of a sleeping bag cut off. The Bottom quilt is the bottom half.

[kitsapcowboy]

One-line answer:

You'll stay warm to the rating of your thinnest insulation.

[Countrybois]

The answer to all 3 of your questions is no.

You'll want an underquilt rated to the lowest temp you expect(10° buffer here is a good idea)

You can then get by with a top quilt rated to your expected temp. Then, if it gets colder, you can supplement with extra clothing or whatever you have.

Sent from my XT1058 using Tapatalk

[zukiguy]

Would you be warm with a down jacket and no pants?? An UQ keeps the bottom side warm and the TQ insulates the top. There's a little bit of fudge factor where people try to use a really over-rated topquilt or sometimes a heavy sleeping bag (0F bag in 20F weather, etc). That never really works out because you still get a kind of cold back and your top side is roasting.

To be comfortable you need adequate insulation top and bottom. For the most part it's the bottom that falls short. On the ground you're really just trying to insulated yourself from the cold ground (conduction) but in a hammock you lose heat through convection, radiation, etc. Don't worry about "over-insulating" the bottom since you can easily vent by loosening the suspension just a bit. In fact, this is how people often end up cold even with adequate gear is because it sags or shifts out of position, creating cold spots.

[Grumpy Squatch]

The answer to all 3 of your questions is no.

You'll want an underquilt rated to the lowest temp you expect(10° buffer here is a good idea)

You can then get by with a top quilt rated to your expected temp. Then, if it gets colder, you can supplement with extra clothing or whatever you have.

Sent from my XT1058 using Tapatalk

This is about right for me. Most of the people I know have settled on using a warm UQ and lighter TQ most of the time. But we are all REALLY warm sleepers. The kind of people who are comfortable at 40 with just a light shirt on. Underquilts can be vented more easily than topquilts so generally have a wider temp range. I find that i use a 20 deg UQ and 40 deg TQ most of the year. In fall/spring I usually use a 0deg UQ and 20 deg TQ. in summer I use a 40 UQ and a fleece blanket.

You can stack... last winter for a -12 deg night I stacked 0 deg and 40 deg top and bottom quilts and woke up at 2am soaked with sweat from being too warm. Good luck.

[FL Hanger]

This is about right for me. Most of the people I know have settled on using a warm UQ and lighter TQ most of the time. But we are all REALLY warm sleepers. The kind of people who are comfortable at 40 with just a light shirt on. Underquilts can be vented more easily than topquilts so generally have a wider temp range. I find that i use a 20 deg UQ and 40 deg TQ most of the year. In fall/spring I usually use a 0deg UQ and 20 deg TQ. in summer I use a 40 UQ and a fleece blanket.

You can stack... last winter for a -12 deg night I stacked 0 deg and 40 deg top and bottom quilts and woke up at 2am soaked with sweat from being too warm. Good luck.

So the poster (and myself) wants to know, how can you get by with a 20deg difference between the uq and tq? Is there some actual science to this differential working? do you tend to get cold on the top and not the bottom once the temps drop in to the delta? According to other posts above, you must have similar temp ratings for both in order to stay warm, but you seem to think different (and i'd like to believe so, too).

[hangingbooger20]

So a member private messaged me this... I asked if it was ok for me to publish... Any thoughts or opinions???

I find it hard to believe that the warmth of one doesn’t supplement warmth for the other, as the two repliers imply. I feel like a uq that goes all the way up past your sides has to create an ecosystem. I disagree that a 20* uq is good only to 70*. I just really feel that there is some science to show that once you’ve created warmth in a space, the external temp isn’t as important as the temp on the external of the top quilt. If you put a space heater in your tent (or even your body temp if sealed, to a lesser degree) and create a warmer ecosystem inside, then your sleeping bag only needs to be warm enough to battle the temp within that ecosystem, not outside of the tent. Shouldn’t that theory apply to the hammock as well? Perhaps it is possible that the uq creates no warmer ecosystem itself? A pad certainly doesn’t. because the pad doesn’t envelope you. perhaps the sock is the barrier that needs to exist in order to trap the heat and create the warmer ecosystem?

What about a down jacket that isn’t zipped in the front (leaving a 10inch gap top to bottom)? If you have ample down to battle frigid temps on your back, arms, neck, but a fleece in the front (that wouldn’t withstand those temps by itself) wouldn’t you be warm enough at that point (providing no wind factor, which wouldn’t exist with a tarp and uq)? I think so.

There HAS to be some science.

[SilvrSurfr]

1. If I have just a 20* underquilt and hammock (with tarp over) will I be warm in 20* weather?
2. If I have a 40* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 20* weather?
3. If I have a 20* underquilt, 20* top quilt, and hammock (with tarp over) will I be warm in 0* weather?

1. You will need a topquilt. The tarp is somewhat irrelevant since it provides no insulative value.
2. Let's hope you have great faith in your 40* UQ, but I don't know why you would expect to get 20* warmth from a 40* UQ.
3. Warm sleeper or not, we're talking about temps that can kill. I've used my 20* UQ/TQ in temps down to 13* F, but I don't play that game anymore.

Nowadays I always carry insulation to provide a 10* cushion over expected lows. So if the expected low is 30* F, I'll carry 20* quilts. If the expected low is 20* F, then I'll carry 0* quilts.

I base this on experience with the weather and weather services. If you are going anywhere remotely remote, then there are not good weather stations nearby. I went on one trip where the weather services said the low would be 18* F, but it was 13* F when I arrived at 6 pm. By 4 am, it was -3* F.

So basically, the weather services were off by 21 degrees. They just didn't have a weather station close enough to where I was going, to properly predict the weather. I don't like being cold and will not rely on weather services for my comfort.