Sleeping Systems
A good sleeping system includes a sleeping bag for warmth, a sleeping pad for insulation and comfort, and a ground cloth to protect your sleeping bag from moisture and sharp objects. A sleeping bag temperature rating of 20° F is generally considered optimal for a Pacific Crest Trail thru-hike. You might choose a lower rating if you sleep cold, or a higher rating if you sleep warm. If you can afford two sleeping bags, you may choose to use a 20° F sleeping bag in the High Sierras and in the Cascade, and use a lighter 35° F bag everywhere else. Some hikers use vapor barrier liners in the colder High Sierras.
Sleeping Bags vs Sleeping Quilts
The warmth of a sleeping bag is determined by the amount of loft (thickness) it has. When you lay down, the part of the sleeping bag underneath you is squished flat. The sleeping bag's fill material that is squished flat doesn't retain much warmth. That's why sleeping quilts were created. Sleeping quilts don't put any wasted fill material between you and the ground.
Still, sleeping bags remain more popular than sleeping quilts. When you roll over when using a quilt you may find that what was once the open bottom becomes the open side. Some hikers complain about getting a draft despite the quilt's draft guard. But quilts work for some hikers, and you may find that they work for you. You may try unzipping your sleeping bag and using it as a quilt for a few nights as a test. The actual weight differences aren't very big. Choose whatever works for you.
Goose Down vs Synthetic Fill
Goose down is substantially lighter and more compressible than synthetic fill. It is also significantly more expensive, and becomes virtually useless when wet. When goose down gets wet, it becomes flat and loses it's loft. No loft means no heat retention. If you try to squeeze or wring the water out of a wet goose down sleeping bag it only gets flatter and more useless. The key to using a goose down sleeping bag is to never let it get wet to begin with. This means waterproofing the sleeping bag's stuff sack (perhaps with a garbage bag or even a kayak bag). If you are sure to keep the bag dry, you'll enjoy greatly reduced weight, and greatly increased compressibility.
Synthetic fill is heavier and doesn't compress nearly as well as down. This means synthetic fill sleeping bags take up more room in your pack. But, synthetic fill sleeping bags are significantly less expensive, and there are several that are light enough and are rated warm enough for a thru-hike. Synthetic fill also looses loft when it becomes wet but, unlike goose down, when you wring the water out of a wet synthetic fill sleeping bag it will immediately regain it's loft. It won't be as warm when wet as it is when dry, but it also won't be completely useless like a goose down sleeping bag would.
Most Pacific Crest Trail thru-hikers use goose down sleeping bags. The weight and compressibility are unmatched, and keeping the bag dry isn't very difficult.
The Lightest Option
The Western Mountaineering HighLite Sleeping Bag ($265) has a temperature rating of 35° F and weighs just 16 oz (1 lb). To learn more about the Western Mountaineering HighLite Sleeping Bag, click here.
Do you sleep a little colder? The Marmot Hydrogen Sleeping Bag ($320) has a temperature rating of 30° F and weighs 25 oz (just shy of 1.5 lbs). To learn more about the marmot Hydrogen Sleeping Bag, click here.
Do you sleep really cold? The Marmot Helium Sleeping Bag ($314) has a temperature rating of 15° F and weighs just 31 oz (just shy of 2 lbs). To learn more about the Marmot Helium Sleeping Bag, click here.
The Cheapest Option
If there is one piece of gear that you don't skimp on, let it be your sleeping bag. A good sleeping bag could easily become your favorite piece of equipment. But if you can't fit a great sleeping bag into your budget, there are some ways you can cut costs. As mentioned above, a synthetic sleeping bag will be cheaper than a down sleeping bag. Also, bags with higher temperature ratings will be cheaper than bags with lower ratings. You may make up the temperature difference by wearing all of your warm clothes to bed. We don't recommend that you try to thru-hike with a sleeping bag with a temperature rating higher than 35° F. You may also consider buying gear used. Finally, if you have to buy new, you can almost always get better deals buying over the internet than you can at brick-and-mortar stores. Google whatever you are looking for and shop around for the cheapest price.
Sleeping Pads
The purpose of the sleeping pad is to provide insulation between you and the ground, and to provide cushion for comfort. Z-rest sleeping pads are very popular, as are the old fashioned blue closed cell foam pads.
The lightest: Gossamer Gear makes a 1/8" thick ThinLight Insulation Pad that weighs 2 oz ($10). They also make 1/4" thick ThinLight Insulation Pads that weigh in around 7.75 oz (also $10). To learn more about ThinLight Insulation Pads click here. Further weight can be saved by only using enough pad to run the length from your head to just below your hips.
The cheapest: The cheapest pads are the blue closed-cell foam pads available at Wal-Mart or Target. They may be a few dollars cheaper than the ThinLight Insulation Pads above. They will also be thicker (and thus, probably more comfortable for you).
Ground Cloths
The purpose of a ground cloth is to protect your sleeping bag from moisture and damage due to abrasion or puncture when sleeping outside of a tent.
The lightest: Gossamer Gear sells the Polycryo Ground Cloth ($8). It weighs just 1.5 oz and will last an entire thru-hike. To learn more, click here
The cheapest: The above option is not only light, but it's cheap. If you want to go cheaper, Home Depot sells 3 mil sheets of plastic cut to size. Even cheaper than that is to make your own out of 42 gallon, 3 mil thick garbage bags. The bags are 50" long and 30" wide when you lay them out. Cut the bag lengthwise to get a sheet that is 50" x 60". Do this to two bags, then join the bags together with a wide tape (such as packaging tape). Cut to size. Total cost: $0.50. You may have to replace this two or three times during your thru-hike. Best to make a few and put them in your resupply boxes.