The Rook™ series is a series of three sleeping bags from the American outdoor manufacturer Mountain Hardwear. The temperature limits of the three sleeping bags range from -1°C to -18°C. All three sleeping bags are available in a unisex version and a women’s version. Here in the test, we tested the unisex version.

General

The Mountain Hardwear Rook ™ 15F/-9C is available in two different sizes. The unisex version is divided into two versions. The Regular version is for people with a maximum height of 183cm and the long version for people with a height of up to 198cm. With both versions, the zipper is optionally available on the left or right side.

During our online research, we came across different weight information. According to the manufacturer, the Mountain Hardwear Rock™ 15F/-9C has a weight of around 1092g. However, the online shop gives the weight as 1125g. We weighed it again and the result was a weight of 1215g including the packing bag. Mountain Hardwear uses an 80/20 mix of down and feathers with a fill power of 650 cuin. The filling weight is about 600g.

Special Details

The Rook ™ 15F / -9C is equipped with a very special thermal collar, as this is not located inside the sleeping bag, but goes around the head opening. This is to prevent cold air from getting into the sleeping bag. In addition, the sleeping bag also has an additional thermal collar, which prevents any cold air from the head area from reaching the lower area of the sleeping bag.

The outer material chosen by Mountain Hardwear is water-repellent, which means that the Rook ™ 15F / -9C can also be used for bivouacking, as the sleeping bag is hereby often covered with dew in the spring and autumn.

Review

In order to test the thermal output of the Mountain Hardwear Rook™ 15F/-9C, we warmed up the sleeping bag and used a thermal imaging camera to see how much heat the sleeping bag emits and where cold bridges occur.

First, we spread out the sleeping bag so that the down can be puffed up properly and maximum isolation can be achieved. To warm up the sleeping bag, we placed three hot water bottles, which we filled with hot water, in the body area of the sleeping bag, as well as a hot water bottle in the head area. We put two glasses between the hot water bottles so that the warm air can be distributed throughout the sleeping bag.

After 15 minutes we took three pictures with the thermal imaging camera in order to see in which areas the Mountain Hardwear Rook™ 15F/-9C emits the most heat. The blue areas on the pictures mean that they have the lowest surface temperature and the further the color changes towards red, the higher the surface temperature at these points is. However, the images cannot be compared one-to-one, as the temperature range is redefined for each image. You can see this from the three temperature indications on the picture (red = highest temperature, green = lowest temperature, white = average temperature).

The overall view of the Mountain Hardwear Rock™ 15F/-9C shows a surface temperature of 10.8 ° C in the middle of the sleeping bag. This is approx. 2 ° C higher than with comparable sleeping bags. One reason for this could be, for example, the low fill power (650cuin) of the down used. Furthermore, two particularly heat-permeable areas are noticeable in the overall view. It should be noted here, however, that these areas were exposed to a particularly high amount of heat during the test. The area in the middle of the sleeping bag that was exposed to the same heat does not show this heat release. From this it can be concluded that the Rook ™ 15F/-9C is better lined in the middle section than in the foot and upper area. In the close-up of the head area, it can be seen that heat emits here both via the seams and the surfaces.

Conclusion

The Rook™ 15F/-9C shows a few weak points in the thermal heat test but is generally a very solid winter sleeping bag. Personally, we were not the convinced by the material that Mountain Hardwear uses, because in our opinion it is not particularly pleasant on the skin and does not feel very cosy.

In summary, one can say that the Mountain Hardwear Rook ™ 15F/-9C is a good winter sleeping bag for all those who focus on price and not packing size and weight.

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