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Reviews > Sleep Gear > Sleeping Bags > Kelty Light Year 3D Synthetic 45 Bag > Test Report by Tim Coughlin


 LightYear 3D 45 Synthetic Sleeping Bag


Product Information



Tester Biography

Initial Report

Field Report

Long Term Report 


8 June 2007

28 August 2007

8 November 2007

full bag


Tester Biographical Information

Name: Tim Coughlin
Gender: Male
Height: 5 ft 11 in (1.8 m)
Weight: 190 lb (82 kg)
Age: 45
Email: TCoug7<at>yahoo<dot>com
Test Location: Western New York, Northern Pennsylvania, Adirondack Mountains
State: New York
Country: United States

Backpacking Background:

I have been an active backpacker for 29 years, with experience hiking in many parts of the continental United States and Canada. Most of my time is spent in the Northeast, especially the Adirondack region of New York State. I practice lightweight and ultralight philosophies when backpacking. Im a seasoned veteran to three-season backpacking, and have been expanding my experience outdoors to include winter backpacking. I am an avid four-season dayhiker. 

Product Information

Name: Light Year 3D 45
Model Number: 33005551
Manufacturer: Kelty
Web Site:

Date of Manufacture: 2007
Temperature Rating: 45 F (7 C)
Shape: Mummy
Shell Material: NPR241T nylon-polyester diamond cross-dye ripstop
Liner Material: P300T polyester taffeta
Insulation: Polarguard 3D

Size Tested:


Listed Dimensions:

Bag Length - 86 in (218 cm)
Shoulder Girth - 66 in (168 cm)
Stuff Size 7 x 16 in (18 x 41 cm)
Fill Weight - 16 oz (454 g)
Bag Weight -
1 lb 15 oz (879 g)

Measured Dimensions:

Bag Length - 84 in (213 cm)
Shoulder Girth - 66 in (168 cm)
Stuff Size - 7 x 13 in (18 x 33 cm)
Bag Weight - 1 lb 14.8 oz (873 g)
Stuff Sack Weight  - 1.2 oz (34 g)
Cotton Storage Bag - 3.0 oz (85 g)

Right-Hand Zipper

Color: Goldenrod/Grey

Lifetime (does not cover normal wear and tear, natural hazard damage, abuse or alterations)

MSRP: $110.00 - US currency
    • Quilt-through construction
    • Chevron stitching
    • Zippered foot vent
    • Differential cut
    • Hang Loops
    • Captured cordlock
    • Snap loops allow bag to be used as a liner
    • Internal loops allow secure points for liners to be used inside the Light Year
    • Fat Man and Ribbon drawcords
    • Ground level side seams
    • Sleeping pad security loops
    • Draft tube along zipper
    • Hip-length, two-way locking zipper
    • Polyester oxford stuff sack
    • Cotton storage sack

Description of Light Year:

The Light Year 3D 45 Sleeping Bag is a synthetic bag shaped in the mummy style.  Features include a hood, draft tube along a partial zipper (opens from the shoulder to the hip area) and a ventilation zipper across the foot area.  Rated at 45 F (7 C), the Light Year 3D 45 bag is a perfect warm-weather (summer) bag.  In its stuff sack, it weighs in at an even 2.0 lb (.91 kg), and measures 7 x 13 in (18 x 33 cm).  It can easily be compressed beyond this if needed. 


Initial Report

The Setting

The test series begins in the middle of the spring season.  Temperatures are warming everyday.  Currently, average daily temperatures are around 70 F (21 C) during the day, with lows of 25 F (-4 C) at night.  It rains often this time of year.  The test will continue through the summer months.   Based on treks already confirmed, testing will include treks in and around Western New York, the Adirondack Mountains, and the Rocky Mountains.  Expected temperature extremes will vary from a high of around 100 F (38 C) to lows near current nighttime temperatures of 25 F (-4 C).  

The Arrival

The Kelty 3D 45 Sleeping Bag arrived in 'new' condition without any discernible flaws.  The sleeping bag is very much what I expected from my research of the Kelty website.  

My Impressions

This is a beautiful sleeping bag.   It is loaded with features, yet maintains a very light finished weight.  The bag appears well made.  Included with the sleeping bag was a stuff sack as well as a cotton storage sack. The bag is two-toned in color: goldenrod (yellow) on top, and gray on the bottom and interior.





The hood is quite roomy, measuring approximately 20 in (50 cm) across and 10 in (25 cm) down.  The Fat Man and Ribbon drawcord is on the right in the picture, and the hook-n-loop fastener for the zipper can be seen on the left.






fat man




Here is a closer view of the Fat Man and Ribbon drawcords.  Both are secured with the same cordlock.  My experience is that I can easily discern which one I'm adjusting simply by using my sense of touch.  The hood's fit is easily adjusted using these drawcords.









The hook-n-loop fastener is illustrated on the left.  This is located at the top of the zipper, just below the hood opening.  Already the small loops are beginning to pick up lint.










The zipper is shown here near its terminus around the hip area.  Each zipper contains a pull.  Both can be operated from either inside or outside the bag.







bag open






Here is what the bag looks fully open.  Although the zipper does not extend all the way to the foot, as in some bags, clearly there is ample room for getting in.  The bag tested has a right-hand zipper, but the bag is also available with a left-handed as well.






Inside the bag, there are four loops.  Two are located on each side of the shoulder area and two are located down near the feet.  These loops are designed to be attachment points for a bag liner if needed.











On the outside of the bag, in approximately the same location as the liner attachment loops are located, are four snaps.  The purpose of these small snaps is to allow the Light Year 3D 45 Bag to be attached and serve as a liner into another bag; thus, creating a multi-season sleep system. 







pad loop



Also along the outside of the bag are four loops located more towards the mid-section of the bag, that serve as attachment points for securing pads beneath the sleeping bag.












Here is a view of the footbox.  The footbox measures approximately 10 x 13 in (25 x 33 cm).  The venting zipper runs across the entire width of the footbox.  This zipper can only be operated from the outside of the bag.  Hanging loops can clearly be seen at each end of the footbox.  These loops are a great way for storing the bag when not in use, or simply airing the bag out.  There are some hang tags also visible in the picture. 




storage sack






Also included with the sleeping bag was an orange cotton storage sack.  This bag is quite large as compared to the bag's stuff sack.  This allows generous air and full decompression of the insulating fill.   In this picture, the storage sack contains the bag.







Although I fit in the range of the regular-sized bag, I opted to test the Large size.  I did this because I wanted the extra room in my summer bag.  The larger bag offers me 6 in (15 cm) in length and 4 in (10 cm) in girth over the regular bag for only 2.8 oz (80 g) more.

The insulation found in the Light Year 3D 45 bag is called Polarguard 3D.  This synthetic insulation is made from continuous filament polyester and is known for its durability and warmth.  According to the manufacturer, it will not mat, clump or pull apart.  It's very durable to repeated compressions, even for long periods and extended use; thus maintaining its insulating characteristics.  Polarguard 3D really shines if it becomes wet.  In my experience, many other insulation materials fail under these conditions, but Polarguard 3D continues to maintain the majority of its insulating ability even if soaked.

This synthetic version of the Light Year is only about 1 oz (28 g) heavier than its down-filled counterpart.

Test Strategy

I believe the best way for me to test this bag is to log as many nights as possible under a variety of conditions to report on its performance.  I live and do most of my backpacking in the Northeast United States, where summers are warm and quite humid.  Fortunately during this test period, I will also be backpacking in the Southwest, where it is quite dry.  Because of the elevations in both the Northeast and Southwest, I expect a broad range of temperatures for testing.  I will experience lows below freezing. 

I guess I would classify myself as a "normal" sleeper - not too hot or not too cold.  I tend to follow most bags' ratings fairly closely.  As such, I am anxious to find out the comfort range for me with this bag.  I like to travel as light as possible, using my clothing to extend the range of a sleeping bag instead of going to a heavier bag.  I feel the Light Year should lend itself to this type of philosophy quite nicely. 

Some specific questions I will be investigating include:

  • How well does the Light Year perform in a hammock?
  • I will try it with a variety of sleep pads to see how well it "stays put" over the pad.
  • I will try the hood with different head coverings and report on comfort and usefulness.
  • I will report on the foot vent and how well it works to regulate heat, especially on those warm summer nights where it's not quite warm enough to get rid of the bag, but it's too warm to be in it completely. I will also report on this scenario with regards to the partial side zipper. This bag does not completely open like a quilt, so the impact of the foot vent might even be greater in the warm weather.
  • I'm concerned that the light colors may be difficult to keep clean. I will report on this over the series.
  • I will report on durability of the bag and the insulation, especially over the span of the test series.



Field Report

Field Conditions

June 15 17, 2007; Alleghany National Forest, Pennsylvania.  This was a three-day, two night weekend trek covering approximately 20 mi (32 km).  The weather was beautiful: sunny skies with 80% humidity during the day and star-filled nights.  Temperatures ranged from 60 80 F (16 - 27 C).  There was no precipitation on this trek.

Juy 18 30, 2007; Philmont Scout Ranch, New Mexico .    This was a twelve-day backpacking trek covering a little over 100 mi ( km) through the Sangre de Cristo mountains with the Boy Scouts.  Elevations ranged from 8,000 12,000 ft (2400 - 3600 m).  There was plenty of rain, especially early on, with temperatures ranging from 38 F (3 C) at night to a high of 100 F (38 C) during the day.  There were also many days and nights of clear skies. 

Field Experience

During the Field Testing phase, I spent a total of 15 nights on the trail sleeping in the Kelty Light Year 3D, and another week of using it while car camping.  I have been very, very satisfied with the performance of the bag thus far.

The Light Year 3D packs very easily.  I found it quite easy to cram it all into the included stuff sack and tie the stuff sack down; yet, I found I could easily compress it still further.  I routinely packed it into a compression sack with the other elements of my summer sleep system including: length Max-Thermo mattress by InsulMat, small down pillow, sleep shorts and tee shirt.  Upon removal from the compressor sack, the Light Year 3D easily expanded back to its normal loftiness and suffered no ill effects from me packing it this way. 

I was concerned that the light color of the Light Year 3D bag might be hard to keep clean.  Instead, my experience was just the opposite!  I spent 5 days of rain on the trail, with 3 days continuous.  Although I took extra care to ensure the bags safety from the elements, sometimes my 16-year-old tent mate son was not so careful.   On more than one occasion my bag somehow ended up under his muddy boot in the vestibule.  I simply wiped it off as best I could.  When the sun finally came out, I laid the bag out for an hour during lunch that dried out any residual mud and I simply beat the remaining dirt out of it.  After the trip, I washed the bag in my clothes washer at home and dried it in my gas dryer on the low-temp setting.  The bag looked (and smelled) like new again.

All of my nights so far have been spent sleeping on the ground in a tent.  Most nights, I used my inflatable mattress.  On the occasions that I didnt use it, I had mixed results.  On the weekend trek to Alleghany Forest, I spent one night simply on the ground sleeping only on the tents footprint.  I slept soundly.  But, on two occasions in the Rockies I woke up from the cold penetrating through the bag when I wasnt on my mattress.  Both of these nights were around 10,000 ft (3050 m) in altitude, quite dry and cool [air temp was near/at bags limit of 45 F (7 C)].

Climbing in and out of the Light Year 3D has not been a problem.  I have found the partial side zipper more than adequate to allow easy entry and exit.  Because it does not extend all the way to the foot of the bag, the bag cannot be completely opened and used as a quilt; although I have found it very comfortable on warm nights to leave the side zipper opened along with the zipper across the footbox.  The hood and cinch cords are easy to operate, even in the dark.

The Light Year 3D is extremely roomy and I love it!  I can find all sorts of positions to sleep in and still be comfortable.  On very cool nights, I took advantage of the hood and cinched it down to prevent heat loss around my shoulders and neck area.  Im really enjoying the extra room the size Large bag Im testing provides me, even though I would fit in the regular size bags range.

The bag retained its insulating properties quite well, even when I accidentally got the footbox wet.  It occurred during several days of rain.  I was camping on a mountain side at a rather steep pitch and constantly slid down all night in my sleep.  The bottom of my bag was coming in direct contact with the tent wall and became quite wet to the touch; yet, I never experience any sort of cold feet from the experience.  The bag stayed wet for three days before I could set it out to dry in the sun.

Ive yet to try securing the bag via the side latch points to a sleeping pad, but I am generally pleased with the way the bag stays put through the night.  I only experienced sliding when I was forced to sleep at a pitch much greater than horizontal, due to location on a mountainside.

I experienced an interesting phenomenon while testing the Light Year 3D in the mountains of New Mexico .  On some nights, it was warm enough to use the bag with the zippers open.  But, on almost any night I fell asleep to this setup, I ended up waking up cold.  Yet, I only felt the cold sensation in local areas.  It was a really weird feeling because when certain areas of my body were cold, there were other areas that were so warm I was perspiring.   Maybe because of my tired state, but It took me a couple nights to figure out what was going on.  The warm areas were underneath me, in contact with the bag and insulated by my inflatable mattress.  I would turn in my sleep, and these same areas would then be exposed to the air with all the zippers open.  While this was comfortable under dry conditions, if the areas had been perspiring, even a little, and then exposed to the dry mountain air, I felt the effects of evaporative cooling on my exposed skin surface.  This in turn would cause me to wake up feeling cold.  I did two things to minimize this: I started sleeping with a shirt on, and I really opened the bag to minimize any perspiration.  This seemed to work for me, yet it was more difficult since it was impossible to open the bag completely.  In time, it was so cool at night this was not even an issue.  I found the whole experience interesting though and wanted to share it.

I have taken this bag below its rating already in this test series and it has performed very well.  As I approached the lower 50 F (10 C) temperatures, I needed to wear more clothing, and really use the hood with it cinched down, but overall the bag really did a great job. 

In summary, I have found the Kelty Light Year 3D sleeping bag to perform outstanding so far in the test series.  I really like this summer bag.

This report will be amended in approximately two months with the addition of the Long Term Report section.   Please check back to find additional information on my experiences and impressions of this product.


Long Term Report

Field Conditions

September 8 - 10, 2007; Rainbow Lake Mountain Resort, New York.  This was a Labor Day weekend camp with the family.  The weather was beautiful: sunny days in the low 70F (21C), and clear nights right around 60F (15C). 

October 6 - 7; Ellicottville, NY.  This was an overnight hike across some state and private land.  Mileage was around 10 mi (16 km).  The weather was a mix: sun, clouds and a ten-minute sprinkle thrown in right in the middle.   Nights were cool, with temperatures hovering around 40F (4C).

During the Long-Term Testing phase, I spent a total of four nights sleeping outdoors using the Kelty bag.  When this is added to the test time of the Field testing phase, I have spent a total of 26 nights testing the sleeping bag.

Testing Experience 

During the long-term phase, I was able to test the sleeping bag while sleeping in my Hennessey Hammock.  It was difficult to get into the bag properly, but this is more indicative of sleeping in a HH (Hennessey Hammock) than the bag.  It is always difficult to align any bag on top the insulating mat/pad in a hammock.  I took advantage of the outside loops to attach my sleep pad to the bottom of the sleeping bag via some stretchable cord.  It worked very well.  I basically climbed into the bag with the pad attached while standing up.  When I was ready, I hopped into the hammock, pad and all.  I don't think this would work with a stiffer pad like an inflatable one, but it worked very nicely with a simple closed-cell foam pad.  Being able to stand before entering the hammock with the sleeping bag on, yet having my feet in contact with the earth was a huge benefit this bag provided.  Once in the hammock, I simply drew my feet in and zippered closed the footbox.

On my last testing trip, I used the Light Year bag with another, smaller bag inserted into it like a liner.  The second bag was also a summer bag, with a 45F (7C) rating.  The night got very cool, with temperatures hitting 40F (4C).  It was probably cooler, but that was the accuracy of my thermometer.  I connected the inner bag to the Light Year at the shoulders by tying it off to the inner loops provided for that purpose.  I slept very warmly that night.

I went over this bag with a "fine tooth comb"; the Light Year shows no signs of wear-n-tear.  I tend to treat my sleeping bags gently, especially in the field since I consider their function so critical to my safety.  The bag looks as good as it did when it arrived four months ago.  I cannot detect any signs of color fading, even though I have washed the bag in my home washer five times.  In order to minimize any effects from washing the bag, I have adopted a method of drying it outside then simply spinning it for a few minutes in the dryer, on the "air" setting, to fluff up the loft.

All of my opinions expressed in the Field Report were further reinforced during the long-term testing phase.  I am very, very pleased with this bag.  It easily packs small, retains its loft, kept me warm even when it was wet, is very durable and shows no signs of wearing out.  The zippers all function as well as the day it arrived.  The zipper across the footbox is great on really hot nights, or for climbing into my hammock.  Best of all, I love the wiggle room this bags provides.  Although it has a mummy cut, it allows me to move around to find my sweet spot for sleeping.  About my only knock is the hood is fairly loose.  But, that's not a bad thing from my point of view because it allows me to wear my fleece hat, does a nice job of eliminating any drafts, and provides me with the wiggle room I love so much with this bag.  So, all-in-all, I have no knocks, only praise for such a nice bag.

Thank you Kelty and BackpackGearTest for the opportunity to test such a great product!


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