Original Zenbivy Bed

35 degree down alps mountaineering quilt. 1.5 pounds. Maybe the best piece of equipment that company has ever made. Or a zenbivy 25 down same weight. Depends on how windy, how much other clothes a I want to wear. Get off the ground if you can with a cot- car camping. Way warmer as the ground is 10x denser than air and sucks the warmth into the ground. A cot also offers better ventilation and you will have to practice venting vs cold.  At some point it will be too cold for you in a 3 season tent and go with a warmer sleep system-   insulated mat with a good r value, wool liner, light wool gloves and balaclava, 0 bag, new tent. Hot water bottle wrapped in your thickest sock stuffed in your bag! Like the folks say here- new dry clothes on a dry body in a dry tent. I've slept in cold on purpose and some really horrible mistakes have been made. 41 is entering the cold zone. 

I have a Zenbivvy Bed with 40 synthetic, 25 down and 10 down (fahrenheit) quilts. Their temperature ratings are comfort ratings. I have slept out with the 25 degree quilt in 25 degree weather and have been toasty warm. And the bottom sheet has a down hood. I would absolutely recommend this system to anyone, especially wider folks and side sleepers.

It's not the lightest. It's not the cheapest. But I sleep in the ground probably 40-50 nights a year and I appreciate the extra comfort.

If you’re claustrophobic, a quilt is definitely the move. I switched to a Zenbivy bed and it changed everything, it feels more like a real bed, and my dog loves curling up on the corner of it.

I would go with a quilt, they are great for moving around. Zenbivy is most peoples favorite, I really enjoy my Big Agnes.

ZenBivy is a game changer!!! The whole set, including pillow, not necessarily their mattress, keeps me snuggly and everything in place while I toss and turn, but I can stick my arms/legs out in warmer weather.

Any thermarest bag is a good start and I've just tried out the ZenBivy and so far absolutely love it. Would also say that a good sleeping mat goes a long way to keep you warm. You could have the best bag for the cold but a weak mat can undo all the work of a good bag!

I have a zenbivy and I love it. Don’t know what their lowest temp rated bag is though

Agreed. As a thrashing side sleeper this bag has been a godsend. It’s super versatile