I no when using it, it seems like it is because of there being to much space
to heat, anywhere were there is space becomes very noticeably colder than
the rest of the bag. I thought at first that it might have been advertised
badly but the bag weighs 2.5kg's which is often more than other -20 bags and
the Dupont filling is meant to be good. I have been thinking about maybe
buying a new bag that is lighter and has a temp rating of around -5 but I'm
not shore weather the same thing will happen again. can anyone suggest a
good sleeping bag, that they no goes down to around -5 and is around £100.
cheers
"Boo" <boo@spam_me_no_spam.net> wrote in message
news:[email protected]...
> Peter Clinch wrote:
> > Andy wrote:
> >
> >> does anyone no how much having the wrong size sleeping bag effects the temperature rating, as I
> >> own a large size vango bag which has a temperature rating of -20c which is to large for me and
> >> whenever the temperature
gets
> >> down to around 5c I have to wear thermals when using it. do you think
it
> >> could be because of the size?.
> >
> >
> > It will have *some* effect, as dead space will allow convection currents to set up rather
> > than still air (which is what does the insulating, the hollow fibre or down just keeps the
> > air still). But not *that* much effect (25C!), as dead space in an overlarge bag tends to
> > just lie flat.
>
> And f course the dead space is itself insulated from the air by the bag itself. So unledd the dead
> volume is enormous it'll just warm up relatively quickly and absorb no more heat after that.
>
> >
> > More likely you either sleep cold and/or the bag is a synthetic past its prime (synthetic bags
> > degrade very sharply after a few years) or a down bag well overdue for a wash.
>
> Or it was misleadingly described in the advertisers' puff.
>
> --
> Boo
