Quick Warmth Sleeping Question (Bag Related)

[Escape Goat]

Hopefully, I can not turn this into yet another what bag question, but I'm thinking of a Spark sleeping bag. Mostly because their limits are lower than my current bags and their weight is around the same as my current bags, there or there about,

Bags I have and suggested limits;
Criterion 350 apparent comfort -6
Cumulus 450 comfort 0, -6 lower (Just Googled and hang on, Cumulus has 100g more and same lower level?! Makes sense that I'm cold in both.)

I know to add approx 5degree for the limit, but I can' guarantee that -6 was bloody freezing at only 200m high last night, weather was around 8degree with rain. Last one in Wales, I stuffed a 250 quilt in too and was chilly I'm not scared of being cold as long as the bag is dry, but I can't always be bothered getting out the tent, going for a walk, star jumps etc to warm up then back in the bag....

My now basic question is, does anyone have either of these and are they warmer, I don't believe the -8 or -15 are think applicable to me because of how my body feels the cold. Realistically I think I need to add 10 degrees to any bag as the comfort level.

-2 comfort, -8 lower https://www.seatosummit.co.uk/products/ ... -spiii-8c/


-8 comfort, -15 lower limit https://www.seatosummit.co.uk/products/ ... -spiv-15c/

Hopefully someone has used these bags as a cold sleeper :)

[whitestone]

Generally with temp ratings: if you are a warm sleeper start with the Limit rating; if you are a cold sleeper start with the Comfort rating. EN13537 (now ISO-23537) only really applies to sleeping bags, not quilts but makers like Cumulus should have an idea how the two compare.

Don't just look at the amount of fill, the fill power needs to be the same as well. Then sizing can also have an effect - too tight or too loose and you'll feel colder.

[Escape Goat]

Ah, fill power is something that I need to educate myself with.


Thanks for the heads-up!

[BigdummySteve]

Don't just look at the amount of fill, the fill power needs to be the same as well. Then sizing can also have an effect - too tight or too loose and you'll feel colder.

I have two RAB bags, one is a Mythic 200 with 900 fill power down as weights under 500g, the other is a much heavier bag, but rated virtually the same.
The heaviest bag with the lower quality down feels cosier and is less liable to cold spots.
I always take the light bag of course, I’m not sure ratings tell the whole story, the foot box on the Mythic is prone to cold spots, presumably where the toes compress the down.

[whitestone]

Ah, fill power is something that I need to educate myself with.

Remember that the US use a different spec for fill power to everyone else! Very roughly take 50 off the US value to get the international standard value, i.e fp900 (US) = fp850(Itnl)

Another variable is down/feather ratio, generally you want more down so 95/5 is better than 90/10. You are unlikely to get higher fill powers with lower down/feather ratio so fp900 and 80/20 is highly unlikely

[Richpips]

I found the Spark quite a tight fit.

[Richpips]

I found the Spark quite a tight fit and therefore cooler than my Mountain hardwear bag which is rated for a warmer temperature.

[Escape Goat]

Hmm, fill power for -8 is 430g of 850+ and -15 has 630g of 850+ but there's 190g more 850+ in the -15 which has 170g more than the Panyam, so logically, I should choose the -15 one for it to be any warmer than either of my two current bags. The -8 is basically the same as my 350+450.

That's helped a lot actually, I've written it down mostly to get my head around it a little better, hopefully I understand better.

Rich, if you felt that it was tight, I may struggle more....


Oh and I don't want it to be huge, I've just had two days with smaller bags and the bike rides so much better, plus I fitted it with a dropper post and bouncy forks now! It's a hooligan!


Thanks!

[Bearbonesnorm]

Weirdly (or is it) a heavier bag can sometimes 'feel' warmer than a lighter (and in theory warmer) bag.

No mention (unless I missed it) of what mat you're using?

[Escape Goat]

I didn't mention mat, I use a Neoair Xlite.

[redefined_cycles]

I didn't mention mat, I use a Neoair Xlite.

Maybe that's your problem there Al...

[Escape Goat]

I know a bag with a higher r number would stop the cold from coming up from the ground, but, I'm cold on my top, not underneath, from what I can gather.

[Richpips]

My winter bag is this - Big Agnes Blackburn UL 0 Sleeping Bag Winter 4 Season -18C 850 FP Down which I use with a Mountain Equipment aerostat down 7.0 mat.

I've used it to -10 and I was toasty and I sleep cold.

[Escape Goat]

What's the pack size on that Rich (in ltrs if you know)

[Richpips]

What's the pack size on that Rich (in ltrs if you know)

Fairly bulky. The mat itself is 3ish litres.

[Escape Goat]

Okedokey. Thanks, I'll do some thinking.

[redefined_cycles]

I know a bag with a higher r number would stop the cold from coming up from the ground, but, I'm cold on my top, not underneath, from what I can gather.

Bet you'll notice a massive change in swapping r value of the mat. I'd say that's where you need to focus first as you already have some top end winter gear in terms of bags/blankets.

Let me know if you wanna borrow my Thermarest (non xlite) and see if that makes a difference first Allen...

[Escape Goat]

Cheers Shaf, will do after some thinking. Appreciate it.

[whitestone]

Stepping back a mo.

What are you wearing when using your current bag/quilt? The tests/ratings assume you'll be wearing a thin thermal layer, technical pyjamas if you like, neither naked nor with masses of clothes. Some people have sweaty feet and simply wearing socks creates a damp spot that cools quicker so they start feeling cold.

I don't know how warm/cool you have your house at night but before the weather gets too warm you could try things out in a cool part of your house/garage/shed. If it drops to 5C or whatever and you are warm under controlled conditions then there's something else going on that isn't down to the kit.

[Scud]

Probably preaching to the converted, but remember that any sleeping bag, down jacket etc is insultation, so it seeks to trap heat. So if you get into the bag cold, you're giving off little heat for the bag to trap. So:

- Exercise just before you climb into bag, some star jumps or the like.
- Eat not long before getting in bag, digestion actually helps generate body warmth.
- Get one of the water bottles off bike, and fill with hot-ish water (not boiling) and place in side a clean sock and place between thighs on femoral artery.
- Make sure none of the insulation is crushed, and that ideally bag doesnt make contact with sides of tent etc.

[Escape Goat]

Cheers Scud, Got those pointers in my regime :)

Currently I have
*Merino Top & bottom
*warm socks
*down coat to move around inside bag
*waffle type jumper.
*variety of different hats not all at once, but maybe I should ha!

I didn't realize the comfort of my bags were around 0 degree, which in my body means about +5. I think a warmer bag would be the answer :)

[JohnClimber]

Feel free to borrow my down Long and Wide winter mattress next time you head out

[Escape Goat]

Thanks John!