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Kelty Light Year XP 40

rated 4.0 of 5 stars
photo: Kelty Light Year XP 40 warm weather synthetic sleeping bag

I had been eyeing the Kelty XP 40 for over a year now, ever since I bought the Kelty XP 0. I was so happy with that bag that I figured I’d stay with same bag but a warmer temperature range. My criteria for selecting this bag were simple:

  • It had to be comfortable sleeping in summer temperature.
  • A Mummy bag with space to move around.
  • Low end of 40 degrees F.
  • A good manufacture with good warranty.
  • Great bang for the dollar.

When I saw the XP 40 on sale for $56 I decide to buy, I bought the long which was a few extra dollars. A little back ground on me will help the review.

I’m male 48 years old, 5’10”, 180lbs. I’m a warm sleeper but getting cooler with age. I do monthly camp outing with my son’s Scout troop and back pack once or twice a year. I like sleeping on my sides but usually end up on my back so I do move around when I sleep.

Cut and Fit:

The XP40 is a generous cut (64”) for a mummy bag which is good in my book. I don’t like a bag I can’t wiggle in. Even though you sacrifice a little in the colder weather the comfort in warmer weather more than makes up for it.  The hood is excellent; truly a great fit and the draw strings can snug it up well in the cold. The hood opening when the bag is zipped up is pretty large allowing me to comfortably stick my head and arm out of the bag, I often sleep with my head on my arm. The bag itself is thin, thinner then the picture would lead you to believe and drapes well around you. The draw strings are great but the holding device is very small and could stand to be larger.


I decided to go with synthetic for several reasons. One it will still work when wet and dries out much faster than down can. Also the new continuous fiber synthetics are very warm but slightly heavier and pack a little larger then down. One big advantage of synthetics in a bag of this temperature range is no cold spots. There is so little down in bags of this temperature range that it is easy to have areas with no insulation or cold spots as you move around. The continuous fiber insulation will never do this; they come in a mat and will not clump up even after many washes. 

Synthetic is also much less expensive then down. This bag uses Climashield XP which is one of the best insulating continuous fibers and from my research will retain heat better with less loft then some other synthetics. The only really question I have is live span and only time will tell.

Build Quality & Materials:

Build quality is excellent, as good as bags costing considerably more. The materials selected are likewise excellent for the following reasons. The materials are very light and soft which gives them excellent draping ability and feels soft next to the skin.

The exterior is a polyester micro fiber; nylon will ware better but is often stiffer. The outer shell is not water proof but will bead water and does provide a far amount of protection. The inside is also polyester micro fiber which wicks away moisture but is very similar to cotton in feel.

Of all the bags I have looked at this material has felt the best to me. It is very comfortable to sleep in. I originally was looking at a high end competitor and was surprised at how much better the Kelty’s material felt, I remember holding the competitors bag and tried to figure out how they could charge so much more for a bag that felt like it was made of lesser quality materials. Zipper all work well and are of equally good quality.


This bag is loaded with great features. There are loops and tie down straps for anything you could think of liners, sleeping pads, hanging loops, etc...  The foot has a zipper to allow addition venting when you are warm. At first I thought this was a gimmick but after using it I am a believer, it is a great way to control the temperature of your bag. The hip length zipper is one low point in my book. I like to sleep with one leg out sometimes to control temperature but the hip length zipper prevents this. One more foot of zipper and it would have been great. A nice surprise was to find that the bag comes with a storage sack in addition to the compression sack. This bag has Kelty’s excellent life time warranty.


OK here is where the tire meets the road. For packing the bag is around two pounds and packs down to a little larger than a foot ball. As I mentioned I bought a long for the extra room 64” in the shoulders vs. 62” for the regular. Stuff sack works well and appears to be water resistance but I don’t think it truly is. I’ve slept out 3 times so far with the bag. On the first outing temps dropped to the upper fifties and I was comfortable in my underwear, bag felt good and I slept well.

The 2nd time the temps dropped to 43 degrees and I woke up a few times feeling just a little cold and I was sleeping in heavy long underwear. I was able to fall back asleep but would wake again feeling just a little cold. Not horrible but it did disrupt my sleep.

The 3rd time was again in the low 40s but this time I had a Coleman fleece bag liners and slept great all night. I again had on heavy long underwear.

So, I think I could use this bag in the 50s but will need a bag liner when it gets in the lower 40s. If I was younger this may have been fine without the bag liner so just remember your comfort will vary.


As with most Kelty products I have owned this bag’s quality is of the highest degree but sells for a very reasonable price. The bag seems to miss its temperature rating by about 10 degrees but might meet that rating with a younger user. For me this is a 50 and up bag.

Overall I am happy with the purchase, the features, engineering and materials are all excellent and the price point and warranty are right on target. I would recommend this bag.

Price Paid: $56

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Regular Long
Price MSRP: $109.95
Historic Range: $59.95-$149.95
Reviewers Paid: $56.00
Total Weight 2 lb 3 oz / .98 kg 2 lb 6 oz / 1.06 kg
Fill Weight 18 oz / .5 kg 20 oz / .56 kg
Length 78 in / 198 cm 84 in / 213 cm
Fits to 6 ft / 183 cm 6 ft 6 in / 198 cm
Shoulder Girth 62 in / 157 cm 64 in / 163 cm
Stuffed Diameter 9 in / 23 cm 9 in / 23 cm
Stuffed Length 13 in / 33 cm 14 in / 36 cm
Shape Mummy Mummy
Temp Rating 40° / 4° C 40° / 4° C
EN Comfort Limit 46° F / 8° C 46° F / 8° C
EN Lower Limit 37° F / 3° C 37° F / 3° C
EN Extreme Limit 12° F / - 11° C 12° F / - 11° C
Insulation Ecopet™ Soft Ecopet™ Soft
Shell Material 40D Nylon Ripstop 40D Nylon Ripstop
Liner Material 50D Polyester Micro Pongee 50D Polyester Micro Pongee
Price $109.95 USD $119.95 USD
Product Details from Kelty »

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