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Marmot Pounder 40 Degree Primaloft Sleeping Bag


Marmot Pounder Sleeping Bag Product Review

The Marmot Pounder is a 40 degree sleeping bag filled with synthetic Primaloft, intended for summer camping. This is a very simple sleeping bag with few frills. It has a full length zipper, a mummy hood, and a slinky nylon shell. When you lie in it or on it, the fill has very little loft. In my experience, I believe that the bag’s temperature is over-rated:  I’ve had some cold nights sleeping in it in 50 degree weather, wearing long underwear.

In addition, despite its name and product descriptions written by the manufacturer, the Marmot Pounder does not weigh 16 oz (in 2008). Try 20 oz.  I personally have a problem with this discrepancy, but I’ll leave it to you to draw your own conclusions.

I bought this bag last year during a period when I was fanatically obsessed with getting my base gear weight under 13 lbs, and chopping 12 oz off my gear list by replacing my 20 degree down bag with a lighter 40 degree bag seemed like an easy win. At the time, I was also smitten by Primaloft, a great synthetic insulator that was becoming very popular among manufacturers of ultralight gear. Primaloft is great stuff. If is highly compressible, very warm, and retains heat even when wet.

When my Marmot Pounder arrived in the mail and I weighed it, I was disappointed that it was much heavier than advertised, but I figured I was still ahead weight wise and decided to keep it. On hindsight, that was probably a mistake and I should have saved my money. The reason is simple. You don’t need a 40 degree bag summer bag. A 20 degree, 3 season goose down bag is completely sufficient for spring, summer, and autumn camping if you understand some of the finer points of temperature management and thermoregulation.

For example, if you have a 20 degree bag and its 80 degrees out at night, sleep in a well ventilated shelter like a tarp tent.  Make sure to position your tent so that the night time breezes flow through it. Evaporation will cool you off, even if your skin is not noticeably wet. Next open up your bag and sleep on top of it or use it as a quilt. Also, reduce the thickness or length of your sleeping pad, so that more of your body heat is sucked into the ground. It took me a long time to understand the dynamics of sleeping pad thickness, but this one variable can make all of the difference in your comfort level, regardless of the season.

This weekend I’m going backpacking with a 20 degree goose down bag in what is predicted to be very hot weather, and I am going to manage these exact variables to stay cool enough for a good nights sleep. Oh, and my base weight is now under 12 lbs, even with a sleeping bag that is almost 9 oz. heavier than the Marmot Pounder.

Disclosure: The author owns this product and purchased it using their own funds.

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  1. Hello Philip. I've been following your website for about a month now, I first found it via Twitter I think. I have found all your reviews and posts helpful.

    About this one, I wish you would have posted it two months ago (and I had subscribed at that time) as I bought the Mountain Hard Wear Ultralamina 45 then. I bought it because I am a big MHW fan and it was on sale (I live in Tokyo where foreign brands are usually marked up significantly) and I am a "hot person," meaning I get hot very easily, so I thought a 45 degree rated bag would be good for all but winter for me.

    I have only used it once, and without a sleeping pad (my new Therma-a-Rest Prolite 4 hadn't arrived from the U.S. yet, it costs $170 in Japan, so I had a friend send it) at an elevation of about 900 meters while in a tent, but on hard dirt on a cool rainy night, about 55 degrees I'd estimate. I wore a medium thickness fleece in the bag and was just ever so slightly chilly. I guess having a sleeping pad would have made a big difference, but still, I felt with the fleece and in the bag and in a tent, I should have been warm enough.

    I guess I will be buying a new sleeping bag after August for this fall!

    Looking forward to all your future posts, keep up the good reviews!

  2. Jason – I've been following your purchases on Twitter this past month to with some envy. You've been picking up some nice gear. Yes, I honestly think you'd be better off with 20 degree bag for 3 season use and I highly recommend the Western Mountaineering Ultralite (28.7 oz). With a good sleeping pad, you should be able to take it down to 0 degrees in winter. As for warm weather pads, I am testing a Torsolite (10 oz) from Bozeman Mountain this weekend. It packs up very small and is 3/4 size so it should be good for warmer temps.

  3. Hi,

    I just ran accross you website, and I love it. This post was particularly interesting to me, because I recently took this the opposite direction. I hope this wasn't a mistake. I live in South Carolina and do almost all of my hiking in the Spring thru Fall seasons in SC, NC, GA, and sometimes TN. I had been carrying a 15 degree mummy bag which I always considered was too heavy and too hot. So after reading an article in Backpacker magazine, I recently bought a Slumberjack Saguaro 45 degree down bag and plan to wear more or less layers of clothes in it to regulate my warmth at night (as necessary). I also just purchased a Big Agnes sleeping pad, more for the reduced pack size and weight than insulation. Can you explain how you estimate the cummulative insulation or temperature of these combined variables?



  4. I don't have a formula but I have found some helpful rules of thumb. A lot depends on external factors such as temperature, wind chill, your metabolism, and the kind of shelter you are using. I think you'll find that your shelter and pad choice will have a much bigger influence on your comfort level than the warmth of your bag or the clothes that you wear, unless they are plastic bags (vapor barriers). Above all you need to experiment and make sure you have enough options built into the system that you bring so that you tweak your entire sleep and shelter system dynamically when conditions change unexpectedly. I guess that's another reason why I prefer general 3 season components over specific seasonal specializations.

    You should also check out these posts:

    Let me know if that helps. Keep asking questions! Thanks for the feedback!

  5. Hi all, I've been reading through all your entries in chronological order with much gusto. Lots of practical information here. At any rate, I must sleep really hot… I use the same MHW lamina 45 synthetic bag, pretty much all year round. I've taken it a good deal below 30 on some nights, and I'm somehow still able to wake up hot, even when using no shelter at all(open cave-camping for example)! The only thing I do, is wear clothing inside the bag if I'm feeling chilly before bed.

    If you happen to sleep "hot" like I do, a synthetic "light-rated" bag can be just the trick! I also don't hate the lightness of the bag…

  6. James – welcome. It does sound like you sleep hot. Good way to save on cold weather gear.

  7. Thanks for you Review,,whew almost made a mistake…I've been looking at the newer version of that bag and have only found negative reviews which I sort of guessed was the Marmot competitiors knocking down the product which I find so much of on so many of the Backpacking websites out there. The amount of fraud is amazing, but I trust you judgement so that may also explain why a $150 bag is now on sale for $99. Thanks

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