Best Semi Rectangular Down Sleeping Bag Of 2021

Categorized as Buyers Guides & Reviews (Camping)

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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. Thus I am here to help you to filter and find the best semi rectangular down sleeping bag from the bags available in the online market.

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

Semi-rectangular sleeping bags are modified 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 temperature about 20F and below. These are made for more insulation and are always bulky to pack. You may want good compression to pack this bag easily.

Summer bags are good for temperature about 30F and above. These types of bags are lightweight because of less insulation and can be packed easily in less space.

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

Temperature ratings

Nowadays temperature rating is mentioned on 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 this that manufacturers are free to claim any rating for there bags.

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

Down Insulation

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

Fill-power is the way to range the quality of 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 is the number the warmer is the down insulation.

Another type of insulation is synthetic insulation which is 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 as your typical raincoat where you get protected by the rain but not with your own sweat flowing inside the raincoat. So the material needs to be breathable as well so that you don’t have to sleep in your own sweat.

A Breathable waterproof bag can cause you up to $100 more.

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 backpack. 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 ensure to achieve the same temperature rating on less down. The easy water repellent treatment virtually eliminates all negative effects that the moisture has on down.

This semi-rectangular bag will not take a large space in your backpack because it is super compressible (according to ASTM standard – a 25-degree regular version have 4.9L compression volume and the 15-degree version have 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 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 the couples enjoying cozy adventures which 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 maxed user height
    • Long: 6ft 4in is maxed user height

This is a low bulk quilt ultralight sleeping bag manufactured using 7D nylon. It has a simple bottom closure to provide comfortable space from shoulder to foot. Nanolite is designed to fit all body types and sizes and is very-very recommend 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 effeciency out of this bag then it is good to integrate it with any mummy sleeping pad.

This bag is very true to its temperature rating so if you’re going to cold places then it is not recommended because you will feel discomfort in it. But, it is a great sleeping bag for sleeping in warm air temperature (Don’t forget its 38-degree, and it’s genuine on its rating)