The North Face Furnace 20 is one of the least expensive and heaviest bags in our Backpacking Sleeping Bag Review. Like the Best Buy winning Kelty Cosmic 20, it uses a combination of lower quality 550 fill down and synthetic insulation. We like this bag for car camping trips because it's warm and comfortable. Lighter and more compressible bags such as the Western Mountaineering Ultralite were preferred for actual backpacking trips.
The North Face Furnace Review
Cons: Heavy, hard to compress
Manufacturer: The North Face
Our Analysis and Test Results
The Furnace 20 is better suited for car camping than backpacking. It is too bulky and heavy to carry any distance or for any extended period. If you're on a budget and you don't plan on carrying your sleeping bag further than the walk-in campsite at the trailhead, this might be a good choice for you.
The other 550 fill down bag in our review is the Best Buy Award Winning Kelty Cosmic 20, which is not as warm as the North Face Furnace 20. We attribute that to the fact that the Furnace has more insulation, a better draft collar, and a closer, more thermally efficient fit for smaller framed testers. The draft tube and passive draft collar on the Furnace use synthetic insulation and are one continuous piece, instead of the floppy piece that Kelty uses for its draft collar.
The Furnace also has synthetic insulation on the bottom of the bag which is intended to be resistant to compression, therefore maintaining more insulation on the bottom of the bag. In truth, we think that this feature adds weight and bulk to it, and you'd be better off investing in a better backpacking sleeping pad than worrying about your sleeping bag providing that insulation.
There's no way around it; at more than 3 pounds, this is the heaviest sleeping bag in our review. Enough said? Low quality down and the addition of some synthetic insulation add ounces to this bag, and the roomier fit requires more material which makes it tip the scales to the heavy side of our testing bunch. By only using down insulation, The North Face could lighten up this bag and make it more packable at that. We're pleased to see that a synthetic bag like the Mountain Hardwear HyperLamina Flame can compare to some of the down bags on the market in terms of weight; HyperLamina: 43 oz., Furnace 20: 50 oz.
The North Face refers to the shape of the Furnace as a "comfort-oriented shape" which is less tapered. Its measured dimensions reflect this, and in testing we noticed the difference. While not as wide and comfy as the Sierra Designs Backcountry Bed 800, it's more rectangular shape is suitable for bigger people and for those that thrash around in their sleep.
The spacious hood of the Furnace is comfortable and the "vaulted" footbox gives plenty of room to move your feet or stuff a damp pair of socks at the end of the bag to dry out overnight without cramping your space.
The Furnace packs down comparable in size to the only synthetic bag in this review, the Mountain Hardwear HyperLamina Flame. No real surprise given that The North Face uses a combination of 550 fill down and synthetic insulation, while the synthetic insulation of the HyperLamina is actually quite compressible for its type.
As we discussed previously, the addition of synthetic insulation to the bottom of the bag is well intentioned, but it only adds bulk and weight to the bag. We did find that the integration of the draft tube and draft collar is a step up from other passive draft collars that we have seen. Adding a way to tighten the draft collar would be even better, because then warm air can be sealed into the core of the bag without having to cinch the hood close to the face. The differential pull-cords on the hood were easy to find and handle during the night, one which tightened the chin/chest of the bag and one to adjust the top of the hood.
Weight and packed size are the biggest limitations of the Furnace 20. It's plenty warm to handle backpacking all summer and dabbling with the shoulder seasons, but it isn't very practical to carry for any distance. Its low price tag and comfortable shape lends itself well to being a go-to car camping and couch-surfing specific sleeping bag.
This heavy bag is best for car camping.
This is an affordable down sleeping bag but we don't think its a do-it-all piece of equipment. We prefer bags that are smaller and lighter to carry on backpacking trips. There's no harm in carrying this bag a couple times into the backcountry, but we expect that you'll be looking for a better bag pretty quickly for extended trips.
The North Face Furnace 20 comes with a low price tag. With that, you also get a few extra ounces and some extra inches to squirm and sprawl about within the bag. As a car camping bag this is a fine choice, but as a backpacking bag you should consider smaller, lighter bags like the also affordable Kelty Cosmic Down 20. Higher-end sleeping bags like the Western Mountaineering Alpinlite and Ultralite utilize better quality down insulation (800+ fill) and lighter, more comfortable fabrics.
— Chris McNamara