I'm a big fan and regular user of the SP2. Mine is the model from a few years back which is not quite as thick and warm as the current SP2 (probably more comparable to the SP1), and I combined it with the SOL bivvy pro to sleep in comfort on a 3 day hike in the snow in the Barrington Tops.
Would you say the Spark 4 is as warm as advertised (eg. truly -8C comfort)? I own this bag, but I haven't been able to test it in cold temperatures yet, and I have a serious trip coming up pretty soon. I also own a cumulus X-lite 400, which is amazingly warm for its weight, and I tend to be a cold sleeper (slept down to -4C in high humidity conditions with the cumulus, despite a -1C comfort rating, no down jacket). I am also a thin and short, so the Spark feels a little bit roomier than i'd like, even with clothes on. Thank you
It's hard to say whether every individual will sleep warm at any sleeping bag rating given the number of variables involved. The average person, sleeping on a good mat in a tent and in a comfortable position, should feel comfortable down to around -8. But, if you are a cold sleeper and you are expecting to regularly be in similar temperatures, I'd recommend going for something a little warmer. ~ Ben
Thanks for the detailed description, very useful. I have a Spark 0 for summer travel. I want to buy the spark for cold season (3 season). How much temperature can boost the "Spark 0" used as a liner inside the "Spark 2" ? Used together can be similar to Spark 3 limti?
The best way to estimate the warmth rating of two combined bags without actually having a lab to test it in, is to add up the total amount of fill of the two bags and compare this to a single bag with a similar amount of fill. This isn't an exact science, you can't mashed two bags together to get the same fill volume and expect it to perform as well as a single bag that is designed to allow maximum loft space for the same volume of down , but it will give you a pretty good estimate. The SP2 has 300g of down, if you add an SP0 at 100g you've got 400g of fill total which brings it in just under the SP3 at 430g. I'd probably allow for some inefficiencies and take a few degrees of the comfort rating, bringing the comfort rating of the SP2 and SP0 combined to about somewhere in the vicinity of 0-2 °C. ~ Ben
Thank you for such a thorough review! I would be glad to know if this bag has more down on its top and less on its back, or if it's evenly distributed on both sides? I know that many sleeping bags tend to have less insulation on the back (relying on your pad warmth), which doesn't work for me, unfortunately, since I'm a side sleeper. I'm asking about Spark III specifically.
Thanks for the kudos, Sophia. The reason the extra fill is needed on top of the bag, is that when the down is compressed it doesn't provide insulation, so while fill is needed on the underside of the bag it is there predominantly to fill the air gaps where your body isn't touching your mat. When it comes to this technical style of bag, they are designed with thermal efficiency in mind whilst making this as comfortable as possible, unfortunately for you the most efficient sleeping position in these is on one's back. I am following up the fill ratio's for you as I am unsure, it's most likely a 60/40 or 55/45 ratio. You may find it to be more worthwhile looking for a roomier bag in which your body can move inside the bag, so when you roll your bag stays in position and you move inside. The Journey is an example of this... albeit a bit heavier - www.snowys.com.au/journey-jo2-wmns-sleeping-bag-8-c. All that being said, depending on your size, you may find the Spark to be roomy enough anyway. Can yo call into a store and give it a test run? I hope that helps. ~ Ben
@@SnowysOutdoors thanks for a quick reply, Ben, that's greatly appreciated. Spark III seemed to be an ideal bag for me much because of its weight to warmth ratio, but looks like I might have to look further because of uneven fill distribution. There is a good chance I will be able to rotate inside Spark III since I'm pretty short and skinny, but it's been a challenge for me in mummy bags mostly because of the hood - I can't rotate rotate with the hood on. Finding a store to try on the bag sounds like a good idea, thanks!
Word from Sea To Summit is a 55/45 top/bottom fill ratio, Sophia. They specifically make the difference between top and bottom marginal to allow for the sleeping bag rolling with the user which is particularly relevant with mummy bags. I'm not sure you'll find a 50/50 split of the fill in any sleeping bags, in my time in the industry they have almost always had more fill in the top than the bottom. I hope this helps with your purchase decision. ~ Ben
Hello, I want to buy a sea to summit but I don't know which one... I do bike packing and climbing/alpinism. I was looking for a light bag with good plumage and that takes up little space. Searching I have found the sea to summit that have very good value for money and good reviews. The subject is the ºC of comfort. The outings that I do by bike are usually in low-elevated areas, so I had thought that the Sea to Summit spark II would be perfect, but I want to do the Ring route in Iceland in summer and I would also like to use it for climbing/alpinism outings in higher areas, so I think you would need the Sea to summit Spark III On the other hand, I measure 1'84cm. and the Regular size is up to 1'83cm but the Large size is up to 1'98cm. Here my question is if the 1'83cm will be too small or if the size Large will have too much bag on all sides and it will not keep me warm. I hope you can help me. Thank you very much! Miki
I think you are best with the Spark III, Miguel, in the large size. The Spark III comfort rating of −2 °C along with the little bit of extra space in the large size makes it versatile for you. You won't feel too claustrophobic and there will be a comfortable amount of space inside to add a liner or extra layer of clothing if you need extra warmth. More importantly, your feet won't be pushing against the end, which I think would be the case with the regular size, then your toes will be comfortably warm in the foot box. ~ Ben
The SpIII & IV have the same length zipper. Not quite full length, even though its called that, stops just above the footbox as per the video. ~ Lauren
We are pretty right for staff in this area at the moment, El Scruffo McScruffy. You can keep an eye on job openings here though - www.snowys.com.au/careers. ~ Ben
Quick question though, how do you find the sleeping mat you're laying on? I've been reading reviews and they seem rate it. Just worried about it being crinkly and noisey
@@elscruffomcscruffy8371 I've never slept a night on the Sea To Sumit Ether mats, so I can't comment first hand sorry. What I can say though, is that they do make a bit of noise albeit not quite as much as the original inflatable STS mats, but the benefits of the thickness and weight these mats offer outweigh the small amount of extra noise they make overnight. These would be my next choice of mat if my 15+-year-old Thermarest ever gives up. ~ Ben
@@SnowysOutdoors legend! I'll be purchasing a S2S sleeping bag and thermal inner liner off you guys soo enough. Just unsure what mat to buy, as you are currently out of stock... Cheers for the advice. Heading to Tassie and can't wait to trial some gear in the winter
You'd have to cut it off, Chris, I'd suggest keeping it somewhere safe if you do this as it has a bit of info on the bag. It's not heavy and isn't an issue to leave attached though. ~ Ben
