I posted before on lightweight sleeping bags for spring/autumn use but have a fleece liner and a blizzard bag (never opened though) and have seen that most people advertise the blizzard bag as two season warmth.

Trying to keep weight to a minimum for a long distance trek during summer conditions (well what we have at the moment) I was considering using this system.

Has anyone had any experience with the blizzard bag as a sleeping bag? Also as I believe its waterproof so with a tarp would I need a goretex bivvy bag?

I have a thermarest sleeping mat and would use this.

You know that nice video-cassette size pack it's in? Say goodbye to that once you open it. They're buggers to repack.

Have done it once. Was warm enough, if a bit rustly!

That's an interesting idea Simon. I have a fleece liner but its quite bulky - so I would only use it for car camping. And it isn't that light either.

So I wonder if this might be feasible: use a normal silk liner inside the blizzard (for comfort only) and put those inside a lightweight bivvy such as a Rab Survival. All 3 combined should be plenty warm for summer. Total weight 170 + 385 + 310 = 865g.

I don't see the point of the bivi bag... unless for a bit of added warmth? But why not just wear clothes for that if necessary?

The blizzard bag isn't in any way breathable (the inner two layers apparently have tiny holes to let moisture move out away from the body, but the outer is impermeable), so no moisture is going to escape out through the bivi, and with a tarp it negates the need to be able to seal your head inside a bivi too... (insect net required possibly?)

Apart from that though, I'd be concerned by the constant rustling I've heard people report - I've been tempted to take mine on hut tours rather than a sleeping bag but never have because of that!

> the inner two layers apparently have tiny holes to let moisture move out away from the body, but the outer is impermeable

Doesn't that mean it will eventually fill with water..?

A fleece liner, in my experience, makes all sleeping bags more comfortable, and prevents that clammy feeling. I guess it's because it keeps you away from the inner fabric with small contact areas.

So, if you're going to use a liner in a non-breathable Blizzard bag, fleece is the thing to go for. I think silk or pertex would end up clammy and rather unpleasant. Fleece would also dry out easily in the morning.

Unfortunately, as has been pointed out, fleece is rather bulky and heavy.

Now, if you could find a micropile liner...

I have a polypropylene liner (aka meraklon) and it is less bulky than a fleece for similar warmth. It also dries much faster than polyester of the same weight. But I can't find any manufacturers still doing them?

John

Dupont make a fabric called Thermolite which has good heat retention properties, and you can buy sleeping bag liners made from it. Google for the 'Thermolite Reactor' liner made by Sea to Summit. It is claimed to add 'up to' 8C to the warmth of a sleeping bag. I don't know about that, but my one works pretty well anyway.

I have thermolite glove liners and they are very cosy for their weight. But my polypro bag liner is thicker than the thermolite bag liners I have seen in the shops. All depends what you need it for...