tent temp: fly no fly

[joefryfry]

Is there a guideline on how much warmer it is in a tent with a rain fly vs not? Trying to decide between a zpacks duplex and a big agnes fly creek. The duplex is lighter and has more room, but I usually carry minimal clothes, so the main consideration is the temp diff.

[TNhiker]

i wouldn't say there's a "guideline" as how much warmer with fly....

too many factors play into it-----is it windy? is the tent in the shade? is the campsite in a holler where the cold will descent? etc. etc.....

and of course, one's own body heat along with maybe someone else being in the tent....

[OwenM]

i wouldn't say there's a "guideline" as how much warmer with fly....too many factors play into it

^^^that, but if you want a point of reference, here's my new MLD Solomid XL and my friend's new Nemo Kunai(he will be out in these conditions regularly, 40+mph winds and whatnot, while they're a rarity for me).
The Solomid is just a tarp, while the Kunai is a double wall 4 season tent.
We both had thermometers attached to our packs, which were inside our respective shelters. Shortly after making camp, his read 28F, while mine read 20F.
20191218_022151.jpg

[Tipi Walter]

^^^that, but if you want a point of reference, here's my new MLD Solomid XL and my friend's new Nemo Kunai(he will be out in these conditions regularly, 40+mph winds and whatnot, while they're a rarity for me).
The Solomid is just a tarp, while the Kunai is a double wall 4 season tent.
We both had thermometers attached to our packs, which were inside our respective shelters. Shortly after making camp, his read 28F, while mine read 20F.
20191218_022151.jpg

Enough said.

[daddytwosticks]

Don't know. But I can definitely feel the temperature difference from inside to outside on my conventional, double wall one person tent (MSR Hubba). If I had to guess, maybe five degrees warmer inside?

[Cheyou]

Not enough difference for me to change any clothing or equipment.

thom

[cmoulder]

Not enough difference for me to change any clothing or equipment.

thom

Indeed.

The comparisons are so subjective and ignore so many variables as to be practically meaningless. The main thing is to block the wind and reduce the movement of air inside the tent. If the lower edges of tarps/pyramids are adequately covered to accomplish this, they can be pretty warm, or at least warm enough.

Duomid with snow around perimeter_edited-1.jpg

[Tipi Walter]

Indeed.

The comparisons are so subjective and ignore so many variables as to be practically meaningless. The main thing is to block the wind and reduce the movement of air inside the tent. If the lower edges of tarps/pyramids are adequately covered to accomplish this, they can be pretty warm, or at least warm enough.

Duomid with snow around perimeter_edited-1.jpg

You pic reminds me of the winter I spent in a Chouinard Pyramid tipi tent back in 1986. It looked something like this---(not my picture)---

1270412680_23487.jpg

These tipi tents were designed by Chouinard as mountain bivouac tents and worked best with snow placed all along the bottom perimeter---thereby reducing spindrift and blown-in cold wind. Without this snow layer the Pyramid got drafty inside and in big blows would lift off the ground like an umbrella and want to take flight. I remember one night on an open bald when I had to spend all night holding the thing down to the ground. And then there's dripping condensation . . . and if the tipi is too small like the Pyramid your sleeping bag footbox will touch the wet fabric wall of the tent.

More pics here---

http://popupbackpacker.com/backpacki...-pyramid-tent/

Full discussion here---

https://intotheoutdoors.wordpress.co...-of-a-pyramid/

A couple years ago I was pulling a March trip and stumbled on this camp of college kids with their Black Diamond Mega Mids---same as Chouinards but different company---

[Deadeye]

Well, without the rain fly, it will certainly be a lot colder in the rain...

Or are you asking if a double-wall tent is warmer than a single-wall? If that's the case, I haven't noticed a difference. It's warmer inside the tent primarily because the wind isn't robbing any heat from you. Tarptent sells a liner for the rainbow and claims it adds 5 degrees temperature difference. Not significant to me, and any ounces spent on another clothing layer would be more effective.

[Tipi Walter]

Well, without the rain fly, it will certainly be a lot colder in the rain...

Or are you asking if a double-wall tent is warmer than a single-wall? If that's the case, I haven't noticed a difference. It's warmer inside the tent primarily because the wind isn't robbing any heat from you. Tarptent sells a liner for the rainbow and claims it adds 5 degrees temperature difference. Not significant to me, and any ounces spent on another clothing layer would be more effective.

This brings up how I think. It's really not a question of fly vs no fly---as all waterproof tents have a rain fly. It's really more a question of single wall tent vs double wall tent.

In their video Zpacks says (of the Duplex) that "Any condensation will run down the wall and out to the downward sloping screen rather than down to the floor" etc.

This is where it's tricky, very tricky---and you hope like heck their advice is correct. In the right conditions ALOT of condensated water will form on the inside of a fly---and the double wall inner canopy will shunt this water off you and your gear and down the canopy sides. A single wall like the Duplex has no double wall protection. Every shake and gust and you brushing up against it can/will/might/might not/certainly will---get you and your gear wet.

[Leo L.]

There are highly specialized winter-/mountain tents that are double wall and designed in a way to save warmth, and are very good at this.
One secret is the distance between outer and inner being a certain amount (about 2 inches) and being the same measure all over the tent. This makes the air gap between inner and outer a perfect insulation.
The general design of said mountaineers tents is such that they are not useful in rain and would do no good for hiking.
So as others have stated here, the main difference is the fly blocking off the wind, especially important for tents that have an inner that has more mesh than canvas.

I have a dedicated tent for winter hiking, an Exped Venus II and it makes all the difference against the MSR Hubba Hubba NX summer tent. I'd estimate the difference at 5-10° between the two tents.

[Tipi Walter]

There are highly specialized winter-/mountain tents that are double wall and designed in a way to save warmth, and are very good at this.
One secret is the distance between outer and inner being a certain amount (about 2 inches) and being the same measure all over the tent. This makes the air gap between inner and outer a perfect insulation.
The general design of said mountaineers tents is such that they are not useful in rain and would do no good for hiking.
So as others have stated here, the main difference is the fly blocking off the wind, especially important for tents that have an inner that has more mesh than canvas.

I have a dedicated tent for winter hiking, an Exped Venus II and it makes all the difference against the MSR Hubba Hubba NX summer tent. I'd estimate the difference at 5-10° between the two tents.

The highlighted quote is very confusing. I exclusively use a 4 season winter tent---a "mountain" tent---and it is designed exactly as you say with the distance between the outer and the inner being about 2 inches and being the same measure all over. And it's the best tent I ever had for long RAINSTORMS---.

No good for hiking?? Not useful in rain? It's my backpacking tent and as mentioned---awesome in a long mountain rainstorm. Please explain.

[Deadeye]

I didn't quite get that one either. As long as you're willing to carry the weight, a mountaineering tent (Hilleberg tents, for example) is a rock solid shelter for any season, any weather.

[Leo L.]

Sorry for my confusing English.
This is the mountaineering (expedition) Sumitomo tent we were using, and I was referring to:
Sumitomo.JPG
This tent provided perfect insulation against wind and cold, how heavy and severe either might be.
But it had no vestibule you could cook in, had not canopy to protect the entrance against rain, had no bugnet, and was not even waterproof. The flap around the whole perimeter of the fly was wide and very sturdy so you could pile snow and rocks around it.
On the other hand it had a toilet opening in the floor...
Not sure about the weight, but we carried it easily together with all the other mountaineering stuff.
Might have had 2 to 3 kilos maybe (remember it estimating at half the weight than my Salewa, which was a bit over 4 kilos).

[CalebJ]

There are lots of single wall mountaineering tents that are engineered for 4th season use and trade waterproofness for breathability and weight. Because rain is a non-issue on a cold high altitude climb, the fabric isn't designed to withstand a long rainstorm. Great in ice/snow/wind. Awful in rain.

Bibler makes several examples of this (Firstlight comes to mind).

[Tipi Walter]

There are lots of single wall mountaineering tents that are engineered for 4th season use and trade waterproofness for breathability and weight. Because rain is a non-issue on a cold high altitude climb, the fabric isn't designed to withstand a long rainstorm. Great in ice/snow/wind. Awful in rain.

Bibler makes several examples of this (Firstlight comes to mind).

Thanks for the input. I know all about what you're talking about cuz several years ago I bought a "state of the art" single wall Integral Designs MK3 tent (now mercifully discontinued) as it was highly praised by several winter experts.

BIG MISTAKE. In a long and heavy winter rain the thing leaked in 9 separate places and twisted my medulla and brainstem back to the safe and secure folds of Hilleberg tents. Oh and I used two tubes of McNett's seam grip on the thing with no results.

[CalebJ]

Sounds about right. It's a very purpose oriented design choice. Great for a high altitude climb but totally wrong for your use.

[Tipi Walter]

Sounds about right. It's a very purpose oriented design choice. Great for a high altitude climb but totally wrong for your use.

I was hoodwinked by experts and previous owners. When I mentioned the leaks they said I must've got a lemon. In part they were right---it's yellow.

[joefryfry]

You've convinced me that The big agnes may be right for me. For me, I would prioritize these things in this order: dryness, warmth, weight, space. It'd be nice to have the space and lighter tent, but not as much as the other two factors. I have a copper spur UL2, but its a tad heavy and I'm giving it to my son. The duplex is lighter and roomier, but I am fanatic about keeping gear dry.

[joefryfry]

I guess it may help to add usage is late spring in southern new england on the AT and northern new england on the AT in summer