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Best Semi Rectangular Down Sleeping Bag Of 2023

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Sleeping bags help to sleep comfortably during the night of camping, hiking, and backpacking. The market has a variety of sleeping bags available. Thus, filtering the sleeping bag is important so that you get what you desired. Therefore, I am here to help you filter and find the best semi-rectangular down sleeping bag from the bags available on the online market

If you are in a hurry, then these are our recommendations:

Semi-rectangular sleeping bags are altered versions of the mummy sleeping bags where the half part has a mummy design and the other half is rectangular.

The main reason to have this bag is – more space than a mummy bag without compromising insulation. The semi-rectangular bag is heavier and bulkier than the mummy bag.

In this article, I will review some best sleeping bags and provide a buying guide so that you can choose ‘the best‘ according to your need.

Related: Best synthetic rectangular sleeping bags (In-depth review)

The Buyer’s Guide

Here are some basic criteria to keep in mind while choosing a semi-rectangular sleeping bag.

Types of sleeping bags

Sleeping bags are of 3 types – Winter, summer, and three-season.

Winter bags are good for temperatures about 20F and below. Intended to offer high-in-class insulation and are always bulky to pack. You may want good compression to pack this bag easily.

Summer bags are good for temperatures about 30F and above. These types of bags are lightweight & compact because of comparably less insulation filling.

Three-season bags means bags that are best suited for fall trips, spring as well as summer also in the mountain where temperatures can drop at night. Good for temperatures about 20F and higher.

Temperature ratings

Nowadays temperature ratings are mentioned in every sleeping bag but you should not see temperature ratings as hard and proof because there is no universal standard system for measuring the temperature of the sleeping bag and because of this, manufacturers are free to claim any rating for their bags.

EN 13537 is a new standardized temperature rating system that is widely adopted in Europe. Some of the US bag manufacturers also adopted this system. This system has given bags a series of ratings which are:

Down Insulation

What does the down insulation mean? Down insulation is the lightest and most efficient insulation type that is based on fill power.

Fill-power is the way to range the quality down. It ranges from about 600 to 900. Here, this figure refers to the number of cubic inches/ ounce the down consumes in a beaker. The higher the number, the warmer the down insulation.

Another type of insulation is synthetic insulation which I am not covering here because you’re here to find the best down insulation sleeping bags.

Fabric shell

This is necessary if you want a waterproof bag, but not if you sleep in a camp. This feature is for those who either camp or hike in rainy places or those who sleep outside or without a camping tent.

The fabric should be breathable and waterproof, it should not be like your typical raincoat where you get protected by the rain but not with your sweat flowing inside the raincoat. The material needs to be breathable as well so that you don’t have to sleep in your sweat.

A Breathable waterproof bag can yield $100 more in price.

2 Best Semi Rectangular Down Sleeping Bag

Ascent Down Sleeping Bag – Best Overall

  • Insulation: Ultra-dry down 750+ loft
  • Temp rating: 25F & 15F
  • Size:
    • Regular: Max user height is 183cm (6ft)
    • Long: Max user height is 198cm (6ft 6in)
  • Certified by R.D.S

If you are buying this, then be ready because you’re getting a lot in this sleeping bag. Ascent down is lightweight, packable, and roomy.

You can easily trust this sleeping bag because it is R.D.S (Responsible Down Standard) certified, which means the feathers used in this bag are coming from humanely treated ducks and geese.

The 750+ ultra-dry down loft ensures achieving the same temperature rating (quality-warmth) on less down. The simple water repellent treatment virtually eliminates all negative effects that the moisture has on down.

This semi-rectangular bag will not take up a large space in your backpack because it is super compressible (according to ASTM standard – a 25-degree regular version has a 4.9L compression volume and the 15-degree version has a 6.2L compression volume), and it is very light so that you don’t have to carry extra pounds on your shoulder.

While minimizing your pack size, it maximizes breathability. Coming to material and shell – this sleeping bag is manufactured lining fabrics and using an ultra-light 20 denier nylon shell.

The rectangular design provides the perfect balance of both space and adaptable warmth and you will get the maximum down lofting for added heat retention by its automatically shaped foot box.

It has a great zip coupling feature for couples enjoying cozy adventures that allows pairing it with the women’s precise right-hand zip bags.

Western Mountaineering Nanolite Quilt – Best for Side Sleepers

  • Insulation: 850+ fill down
  • Temp rating: 38-degree
  • Size:
    • Regular: 5ft 8in is max user height
    • Long: 6ft 4in is max user height

This is a low bulk quilt ultralight sleeping bag manufactured using 7D nylon. It has a simple bottom closure to provide a comfortable space from shoulder to foot. Nanolite fits all body types and sizes and is highly recommended to side sleepers because it is rectangular on top and mummy on down.

The top collar of the bag drapes around the shoulders to lock them in heat and its 850+ fill down is very light, warm, and compressible.

If you want the maximum efficiency out of this bag, then it is good to integrate it with any mummy sleeping pad.

We can say it satisfies temperature rating, so if you’re going to chilly places then it is not recommended because you will feel discomfort in it. But, it is a great semi rectangular sleeping bag for sleeping in cold air (Don’t forget its 38-degree, and it’s genuine on its rating)

Mummy vs Rectangular Sleeping Bag

It all comes down to the shape of it; mummy sleeping bags look exactly like the ancient Egyptian mummies and rectangular sleeping bags are rectangular. Each has its benefits like mummy sleeping bags are compact, form-fitted, better warmth as less air can seep in.

While rectangular sleeping bags are great for side sleepers as they provide enough room to test different sleeping positions. The warmth is comparably less and is less compact. Warmth is an inconsistent variable that depends on insulation used, fill power, and fill weight.

Semi-rectangular sleeping bags are the mutation of mummy & rectangular sleeping bags. Up to the middle part, it’s more like a rectangle & from middle to bottom, it’s more like a mummy. According to my experience, this version of the sleeping bag is highly under-rated as it can provide warmth & comfort in one pack.