I was looking at this quilt: https://www.amazon.com/Paria-Outdoor-Products-Thermodown-Sleeping/dp/B07BGGB7R2/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1&psc=1

Looks like a good price. But I'm confused about one thing. Looking at the photo and the way the quilt snaps on the bottom, wouldn't it be better to just put a zipper in it? I don't see the advantage of this quilt over a rectangular sleeping bag, which you can open up like a quilt if you want.

The weight seems good---2 lbs 1 oz for 30 degrees. But my semi-rectangular 35F bag weighs 2 lbs 4 oz with a hood and is good to 30F comfortably.

I realize that you can get lighter 800 down quilts . . . for a lot more money. I'm trying to see an advantage of this reasonably priced Paria 30 quilt compared to a sleeping bag.

Having a foot box that can be opened and closed allows for temp control. Open the foot box if you are hot, close it up if you are cold. If it's really warm out you can unzip it completely so it lays flat.
Quilts are designed as such for use sleeping in a hammock, although ultralight ground dwelling campers have moved toward them as well for the weight savings. It's very difficult to get in and out of a sleeping bag when you are laying in a hammock.
For that price you could get an Econ Burrow top quilt by Hammock Gear, a very reputable cottage vendor putting out an excellent quality product.

"It's very difficult to get in and out of a sleeping bag when you are laying in a hammock."
So very true.
Are temp ratings on top quilts true to claims?

unshavenman: "Having a foot box that can be opened and closed allows for temp control. Open the foot box if you are hot, close it up if you are cold. If it's really warm out you can unzip it completely so it lays flat.
Quilts are designed as such for use sleeping in a hammock, although ultralight ground dwelling campers have moved toward them as well for the weight savings. It's very difficult to get in and out of a sleeping bag when you are laying in a hammock.
For that price you could get an Econ Burrow top quilt by Hammock Gear, a very reputable cottage vendor putting out an excellent quality product."

My down sleeping bags have a foot box that can be opened and closed. I don't use a hammock. The weight savings seems to be 3 oz. in my case, but to save 3 oz. I would give up insulation on all sides and a hood (LL Bean semi-rectangular 35 with hood; my previous model weighs 3 lbs 4 oz.). I can see why hammockers would like quilts. Still not seeing any advantage for ground sleepers compared to a sleeping bag that's a bit over 2 lbs.

I have an Enlightened Equipment RevX Top Quilt. 30º rating, Non-Tapered, Snap/cinch cord footbox that I use June-Aug. I'm claustophobic and the quilt makes it feel like your bed. The cinch cord footbox is really nice as well as the snap at the top that keeps the quilt on you. Packs very small and allows for a much greater temp range than my sleeping bags in hot weather.

mjmkjun: " "It's very difficult to get in and out of a sleeping bag when you are laying in a hammock."
So very true.
Are temp ratings on top quilts true to claims?"

Temp ratings are subjective, and whether one is a cold sleeper or hot sleeper is also an important consideration. However, the reputable cottage vendors (for example Enlightened Equipment, Underground Quilts, Hammock Gear) stake their reputations on satisfied customers, so they typically overfill the down to allow for a conservative temp rating.

Try loco libre quilts, excellent company for a bit less than the other quality quilt companies. They have a saver series budget quilt, the serrano, still excellent, 800 fill , 30 degree, 20 oz. $170.00.

I like the product and it looks interesting. Here's another option:

I have an REI Big Cat down bag that I seldom zip all the way up. It's made wide as I'm a big guy and I sprawl. I gotta be able to bend my legs significantly when I sleep or I wake up very sore.

I seldom zip it up. Rather, I sleep with the bag draped over me, with the bottom of the bag actually covering my body, and the zipper zipped all the way down. I put my feet in the footbox. In essence it becomes exactly like the picture the OP linked to. I like this arrangement because:

1. I'm a stomach sleeping sprawler, and I have arms and legs all over the place. It's less confining.

2. I'm finicky temperature-regulation-wise, and my arrangement allows me to merely lift up a side to allow air in if I'm too hot.

3. I always have the option to zip it up, which I have done at times when the temp drops.

Every year I struggle with the idea of bringing in blankets rather than a sleeping bag. Blankets would be heavier and bulkier, but they would offer more flexibility. I also like the fact that voyageurs and trappers used blankets before sleeping bags. I kinda like that thought. (Yes I use a stove and other 20th century conveniences the voyageurs did not.)

Mike

MikeinMpls: "I have an REI Big Cat down bag that I seldom zip all the way up. It's made wide as I'm a big guy and I sprawl. I gotta be able to bend my legs significantly when I sleep or I wake up very sore. I seldom zip it up. Rather, I sleep with the bag draped over me, with the bottom of the bag actually covering my body, and the zipper zipped all the way down. I put my feet in the footbox. In essence it becomes exactly like the picture the OP linked to. I like this arrangement because:
1. I'm a stomach sleeping sprawler, and I have arms and legs all over the place. It's less confining.
2. I'm finicky temperature-regulation-wise, and my arrangement allows me to merely lift up a side to allow air in if I'm too hot.
3. I always have the option to zip it up, which I have done at times when the temp drops.
Mike"

This is exactly why I'm having a hard time seeing the advantage of a quit. Your sleeping bag serves the exact same purpose as a quilt, with the added advantage of #3, that you can zip it up if you want. I only zip up my sleeping bag if I wake up cold in the middle of the night or it's real cold at bedtime. Otherwise I use it quilt style.

Advantage of a quilt is that it weighs less and compacts more than a bag of similar rating. If you use your bag primarily as a quilt then its a good way to reduce bulk and weight.

Short answer is, if you aren't hammock camping or not trying to shave weight, then there's really no good reason to use a top quilt instead of a sleeping bag.

I switched to a quilt because I can't sleep in a mummy bag because it's too restricting for me and my rectangular bag was to bulky even for a higher temp rating(so I was still cold most nights because it wasn't rated low enough). So I got a quilt because it packs much smaller and weighs less even with a lower temp rating. It's also much roomier than a rectangular bag ( ordered it extra wide and tall and it' still smaller packed up and weighs less). I don't get drafts if I don't want them(setting up the pad attachment straps correctly) or I can set it up without pad attachments and get as much ventilation as I need. I'm a stomach and side sleeper, so hoods on bags are just a pain that I don't need. On cold nights I sleep with a hat on. I've never slept warmer or more comfortable. One of my tripping partners switched last year from a nice mummy down bag to a quilt and he couldn't believe how much warmer and comfortable he was as well.
We can now get our quilt, sleeping pad, pillow and hat in a smaller stuff sack then a rectangular bag that isn't rated as low of a temperature. We single portage and can get all our gear and food into two packs. One guy takes larger pack with tackle box attached to it and paddles. Other guy takes canoe with fishing poles strapped into it and smaller pack. We trip very comfortably with chairs, multiple tarps and other things that some people would say is unnecessary, but we want to be comfortable and relax. It was the easiest way to reduce bulk in our packs without sacrificing comfort.

unshavenman: "Short answer is, if you aren't hammock camping or not trying to shave weight, then there's really no good reason to use a top quilt instead of a sleeping bag."

so true, my tent, I am warmer in my sleeping bag, in my hammock, I am warmer in my top quilt with underquilt below me.

Once you understand the pros and cons of materials and construction the decision as to what will work best for you is dependent on weather conditions and personal preference.

In general a quilt is a sleeping bag with no zipper and open underside. Used similar to a blanket, you lay directly on the sleeping pad and tuck the sides in as needed. Quilts are lighter and more compact than a similar constructed sleeping bag because there is no material or insulation on the underside.

My personal preference is a down insulated sleeping bag with open horizontal baffles that allow me to move the insulation from top to bottom in order to regulate temperature. I use a rectangular bag in warm weather and a mummy in cold weather.

I own the Paria Outdoors 15 degree quilt in Long/wide. I've only had it a few months now, so I haven't had it down to or below 15 yet, but I have spent a few nights in the upper teens/low 20's, and it has performed quite well. That said, I was using it in my hammock with my HG 0 degree incubator UQ, so that most certainly helped retain warmth. Overall, I am quite pleased with the top quilt so far. For the price, its practically a no brainer.