The top bag sleeping system has been tried and tested many times as a way to reduce weight and bulk. The idea came from sleeping bag designers. They thought that when a sleeping bag was used on a sleeping mat, there would be no need for the bag to have insulation along its base, as the mat already provided plenty of insulation in this area. But thus far it is probably fair to say that the concept has never really taken off. So can Therm-a-Rest, a brand best known for its range of self-inflating mats, make this approach work?
The Haven Top Bag is designed to accommodate a tapered self-inflating mattress inside, such as a Therm-a-Rest ProLite. This then provides draught-free insulation along the back. In warmer weather the Top Bag can be secured on top of a sleeping mat by using two supplied straps, so they form a single unit.
The theory is that this all saves weight. The Haven weighs 695g and has an EN13537 lower comfort limit of -6 deg C. So it could be compared to a 3-season bag such as a Mountain Equipment Xero 550, which is 979g and £270 or a Rab Alpine 400 at 1090g for £260, as featured in Trail Spring 2010. The Haven is a little smaller overall than these bags, but it clearly has a major weight advantage, and at £190 it brings a big cash saving too.
But the problem is that when you roll over onto your side in the night, the sleeping mat stays on your back. As the bag is very narrow it is hard to move inside the bag without the mat sticking to your back as well. Also, there is no zip on the top or side to allow you to ventilate the bag.
Price £190 (size L)
Outer fabric 20D nylon ripstop
Inner fabric 30D nylon
Fill 330g of 700 fill power down
Lower comfort temperature rating -6 deg C
Packed size 18x20cm
Weight 695g (size L)
Made in China
Stockist details tel. (01629) 580484; www.cascadedesigns.com
The Top Bag saves weight, offers good value for money and there are plenty of people who rate this kind of system, but it doesn't ensure a comfortable night’s sleep.
Review by Graham Thompson
First published in Trail magazine August 2010