Rectangular sleeping bags are the most spacious models available. They offer greater freedom of movement and a comfort level that feels similar to sleeping under a blanket.
On the other hand, their larger interior volume creates more space that needs to be heated, making them less efficient at retaining warmth than mummy sleeping bags. As a result, they are particularly well suited for warm summer nights.
Because of their larger size, they are also bulkier and take up more space when packed in a storage or compression sack.
If you choose a rectangular sleeping bag and occasionally camp in cooler conditions, consider bringing warmer sleepwear to stay comfortable throughout the night.
Ideal for: warm nights, summer camping, campers who prioritize comfort and space, and adventures where weight is not a major concern.