The Macpac Epic 450 SF has a lightweight highly water-resistant/breathable shell and lining, is fully seam taped, and has a short water-resistant zipper. It’s functionally an insulated bivy sack.
The 450 SF is the warmest of Macpac’s Epic series, containing 16 ounces (450 grams) of 750 fill-power down. Its European rating of +3 °C Comfort/-2 °C Limit of Comfort/-19 °C Extreme, is roughly equivalent to a 30 °F rating by US standards. I measured the weight of the bag at 31.2 ounces. (For clarification, the Macpac Epic series only uses the name “Epic”; it does not use the water-repellent Epic fabric by Nextec.)
Sleeping in the Macpac Epic 450 SF sleeping bag inside an igloo. I’m wearing extra clothing inside the bag in this photo. The temperature is 31 °F inside and 16 °F outside.
The outer shell fabric is Reflex LoftPro, which is a proprietary polyurethane laminate with a ripstop nylon face, weighing 2.2 oz/yd2. It has a hydrostatic head pressure of 10,000 mm/14.2 psi and moisture vapor transpiration rate (MVTR) of 15,000 g/m2/24hours. The previous Pertex Endurance shell used on this bag is about the same weight but its waterproofness and breathability are significantly lower (2 oz/yd2, hydrostatic head pressure 1,500 mm/2.1 psi, MVTR 9,000 g/m2/24h). Both fabrics have a thin PU membrane, which is hydrophilic and absorbs water. It works by absorbing water vapor, moving it through the membrane as a liquid, and evaporating it from the outside surface (which is a slow process). For comparison, air permeable eVENT fabric has a MVTR of 27,000 g/m2/24h.
Macpac uses a proprietary Stitch-Free construction technology to attach the bag’s outer shell to its inner lining via short box wall baffles. This unique seam taping technology preserves the integrity of the Reflex LoftPro shell, eliminating the possibility of leakage through stitched seams. The VapourLite lining has a DWR finish which causes water to bead up on the surface, but it is not waterproof.
The outer shell on the Macpac Epic 450 SF (left) is Reflex Loftpro (a proprietary polyurethane laminate with a ripstop nylon face) seam-taped to a VapourLite lining (a ripstop nylon taffeta with DWR). There is no stitching through the outer shell. The bag comes with a waterproof dry bag style stuff sack (right).
Macpac emphasizes that this bag is targeted to the adventure sports niche, where the intended use is minimalism - grabbing a few hours sleep under the stars and getting back on the trail. But it has potential to be more. For us lightweight and ultralight backpacker types, it means we can leave the bivy sack at home, because the Epic bag is functionally a bivy sack and sleeping bag combined.
Think about it - if you sleep under the stars, use a poncho-tarp or ultralight tarp for shelter, or sleep in a snow shelter - chances are you also take an ultralight bivy to protect your sleeping bag from condensation or spindrift. Alternatively, you can use a “waterproof” sleeping bag and leave the bivy at home. The weight savings are partly offset by the 30-denier Reflex LoftPro shell material, 30-denier VapourLite lining, and seam taping, which are heavier than the 20-denier Pertex Quantum (0.9 oz/yd²) shell and lining used on many ultralight bags. Overall, the water-resistant fabrics and construction add about 3.5 ounces to the weight of the bag.
Since the Epic 450 SF is designed to be a minimalist lightweight highly water-resistant bag, its feature set is Spartan. It has a short (15 inch) contoured water-resistant zipper on the left side (left photo). Inside, there is a double pull drawcord that closes the hood snugly and evenly around the head and face (right photo), and the hood has a small brim.
The bag’s girth is also Spartan, with 58 inches at the shoulders, 48 inches at the hips, and 32 inches at the foot. The tight cut is for adventure racers who want to save space. The slender cut may be sufficient for a trim person or an adventure racer, but it doesn’t leave much extra room for the average person, and it’s definitely too tight for a large person. The size XL is simply 6 inches longer, but not any wider. That said, I (6 feet, 170 pounds) did reasonably well wearing extra clothing inside the Epic bag. The tighter fit was not my preference (I prefer about 62 inches of shoulder girth), but I successfully wore insulated clothing inside the bag both summer and winter and kept warm down to 22 °F. The trick was to turn over with the bag, not inside the bag.
I slept in the bag on eleven fall and winter backpacking trips in a variety of shelters - under the stars, under a poncho-tarp and tarp, inside single wall and double wall tents, and inside two igloos. The conditions included dry and pleasant, two early fall snowstorms in a single wall tent, a windy/rainy night under a poncho tarp, heavy tent condensation, and high humidity inside an igloo.
Is the bag truly waterproof? Well, almost. Water droplets roll off the shell, and there is no exposed stitching for the water to soak through. The lining also sheds water. In that regard it performed just like a bivy. I also found that very little water soaks through where pressure is applied, such as a puddle under the hips or sleeping on top of wet ground. That’s a situation that doesn’t happen very often, or can be avoided. In one early fall snowstorm I had wind-driven snow drifting inside a single wall tarptent, and I stayed dry and warm in the Epic bag.
However, when I slept inside a cold high humidity tent or igloo, the bag did absorb some moisture. I weighed the bag when I got home from two igloo camping trips and found that it had absorbed 2.5 ounces of moisture on the first trip and 2.2 ounces on the second trip. Thus I conclude that the bag is unlikely to leak directly through the shell, but it does tend to accumulate some moisture over time, especially in a high humidity environment. The source is probably body perspiration which is either absorbed by the polyurethane membrane or unable to pass through it under cold damp conditions. The amount of water absorbed is enough to reduce the bag’s loft and warmth. Macpac recommends (and I agree) that it is a good practice to turn the bag inside out and air it out every day on a longer trip.
The functionally waterproof Macpac Epic 450 SF sleeping bag provides an extra measure of dry butt insurance while sleeping under a minimalist spinnaker poncho tarp.
I found the Macpac Epic 450 SF to be about right for summertime backpacking in the Rocky Mountains, where nighttime temperatures can drop down to freezing . By wearing my camp clothes inside the bag, I was able to push it down into the 20’s F, which is enough for spring and fall backpacking. It’s also sufficient for sleeping in a snow shelter or hut where the nighttime temperature doesn’t go much below freezing.
Missing from this review (and for all sleeping bag reviews published here, for that matter) will be an assessment of whether or not the sleeping bag performs adequately at temperatures near its manufacturer-reported temperature rating. Click here for the complete Backpacking Light Position Statement on Sleeping Bag Temperature Ratings.
Within the waterproof sleeping bag category, the Macpac Epic 450 SF is quite similar to the Exped Ibis WP bag. The Ibis has a Pertex Endurance shell and nearly identical insulation, but weighs 10.8 ounces more. However, the shoulder girth is 2 inches wider (1 inch more in size long), and it costs $30 less.
Comparing the Macpac Epic 450 SF (750 fill down, Reflex LoftPro shell) with the popular Marmot Hydrogen bag (850+ fill down, Pertex Quantum shell), the Macpac bag comes out approximately 10 ounces heavier and $91 more. The weight difference is due to the heavier shell fabric and lower fill power down in the Macpac bag. The cost difference ($91) is almost enough to buy a lightweight bivy, so that’s close to a wash. Personally, I would rather have the Marmot Hydrogen bag plus a lightweight bivy for my $400 because it provides more versatility. However, if Macpac were to go to 850+ fill power down in their Epic bags, the decision would be more difficult.
Given the narrow shoulder girth, I found the bag’s short water-resistant zipper a bit cumbersome to operate. Also, there is no foot ventilation, so ventilation is likely to be an issue in warmer, more humid climates. The nylon taffeta lining is quite supple and adequately downproof; with only an occasional feather coming through.
Features and Specifications
- Manufacturer: Macpac (www.macpac.com/)
- Year/Model: 2006 Macpac Epic 450 SF
- Style: Water-resistant, zippered, hooded mummy bag
- Insulation: 16 oz of 750 fill-power down
- Construction: Fully seam taped waterproof/breathable shell, water-resistant lining, short box wall baffles, 6 inch insulation chambers
- Loft: Measured double layer loft (several locations) averages 4 in; manufacturer specification not available
- Temperature Rating: +3 °C Comfort/-2 °C Limit of Comfort/-19 °C Extreme, which is roughly equivalent to a 30 °F rating by US standards
- Fabrics: The outer shell fabric is Reflex LoftPro (a proprietary PU laminate with nylon face, 2.2 oz/yd2 (63 g/m2), hydrostatic head pressure 10,000 mm/14.2 psi, moisture vapor transpiration rate 15,000 g/m2/24hours; the lining is 30d VapourLite ripstop nylon taffeta with DWR
- Features: 15 in water-resistant zipper with draft tube, double pull hood closure, small brim on hood, hang loop, waterproof dry bag style stuff sack
- Weight: Measured weight 31.2 oz, manufacturer specification 29.9 oz; dry bag stuff sack is 2.2 oz
- MSRP: $400 US