Sleeping Bag & Quilt Pairing

“It depends” :)

Air temp., pressure, humidity – both affected by altitude – dew point, shelter, wind, will you have a sunny lunch stop to dry the over bag, how many nights out, etc., etc.

You might try carefully weighing the over bag every night/morning and see how much water it actually accumulates.

Thinking about it makes me wonder about using two synthetic bags along w/ a down bag.  The synthetics always sandwich the down, but you alternate which synth layer is inside vs out from one night to the next – the wet one gets it’s own stuff sack.  The theory being that the wet one will get dried off the next night so your net water accumulation is depended only on conditions, not how many nights you’re out.  But of course, this means more weight and bulk.

The other option is a vapor barrier.

But if you’re not noticing any difference from the start of your longest trip to the end, maybe it’s not broken enough to bother fixing.

Thanks for the reply Rene. Any other input or experience on using a down or a synthetic quilt as the outer bag?

For cold weather backpacking I prefer either a single down mummy with a VBL, or a lighter down mummy or quilt (20 or 30F) paired with a synthetic over-quilt (50F) on top. The 50F quilt is great for low altitude summer car camping trips where it never gets lower then the mid 50’s at night.

For the the over-quilt, I went extra long and extra wide with a toe box that opens. The extra size avoids compressing your down “underbag” when pairing. And the open-able toe box lets you adjust leg/toe volume if needed, or open it up completely in summer. This was a pretty simple and inexpensive MYOG project – the hardest part was making enough room to cut the fabric!