by blacksheep » Fri 22 Feb, 2013 8:35 am
Moondog is on the money, as is Rucksack.
For most Vic high country use (assuming good shelter and good sleeping mat), a "five inch bag" will do the job for most (ie: the thickness of the bag at center of core is 5 inches thick. In simple terms the thicker the bag, the more it slows heat loss and therefore more suitable for cold temperatures. The correlation to thickness (loft of the bag, measured at the chest) and comfort temperature range is roughly as below-
-10 degrees - 6 inches
-5 degrees - 5 inches
0 degrees - 4 inches
5 degrees - 3 inches
So, as Moondog says, 70mm single layer (140mm double/5.5 inches) should suffice for Vic highcountry use.
All the ways the thickness of insluation is achieved (fill power of down/ species of down etc) don't really influence warmth, but rather weight/packable size (and price!) of the bag. The height of the insulation is the measure of warmth.
Loft can be rejuvianted with washing/drying if required, but take care, as the baffles are easily damaged if a moving a wet bag.
I have cut/pasted this info directly from our website, under sleeping bag care...
Cleaning Your Down Sleeping Bag
We recommend hand washing your sleeping bag, but it must be done carefully. Rough handling can tear the interior baffles. A washing machine should not be used.
Use a non-detergent soap. Specialised down soaps are available from good outdoor stores. Fill your bath with enough lukewarm water to cover the bag. Work the suds in gently. Do not twist or wring your bag.
Rinse until all the suds stay white, two or three times at most. Rinse thoroughly the last time to remove all traces of soap. Press firmly but gently to remove as much water as possible.
When carrying your wet bag ensure you support it entirely to prevent any internal damage caused by the wet and heavy down.
It is best to dry your bag naturally over a period of time. Initially lay it flat on the floor. Once partially dry it can be hung outside. Warm windy days provide the best drying conditions.
Finally your bag can be tumble dried on a gentle cycle. You must use a large commercial drier. Do not use a household dryer.
The down may clump together in the drying process. These clumps should be broken apart gently by hand, or if a drier is used, place a tennis ball in with the bag to prevent clumping.
Do not dry clean your sleeping bag. Some dry cleaners may offer a washing and drying service for down filled items, check with them first.
NOTE: By using a sleeping bag liner you can keep your bag cleaner for longer, minimising the need to wash it.