Other than persistent heavy rain and gale-force winds, few things spoil caravan holidays more than being cold at night. But shivering your way through the early hours is completely unnecessary because – whatever time of year you choose to go away – there is a sleeping bag available that will guarantee that you get your 40 winks at a comfortable temperature.

However, buying sleeping bags is much more complicated than it used to be. At one end of the market are traditional, envelope-style bags – at the other extreme are ‘mummy’ bags that support comfortable sleep in the most absurdly cold weather. 

In the middle, though, are numerous clever designs that try to offer the best of both worlds: combining the comfort of traditional bags with the superior modern materials and design features of more advanced products. 

In the Practical Caravan test we kick off with the most important factor of all: comfort. We evaluate each bag for size and roominess, and closely examine the materials used. Synthetic fabrics traditionally tended to be uncomfortably coarse and shiny, but great strides have been made in materials technology. And synthetic fabrics aren’t without their benefits.

For instance, we look favourably on products that can be machine-washed. Because drying a bag can often be difficult, too, built-in hanging hooks – which mean that a wet and heavy example can be hung out straight rather than folded over a line – are a bonus. Better still are sleeping bags that can be tumble-dried.

Another benefit of the latest materials is the reduction in size: thanks to modern fillers, warm sleeping bags no longer need to be huge. But a decent storage sack – preferably one that allows you to compress the bedding – is essential to minimise pack-down size.  

Zips are another area that we focus on in this group test. We prefer those that open fully: in other words, right down one side and across the bottom. Not only do they make cleaning (as well as getting in and out) easier, but they also usually make it possible to join two single bags together to make a double sleeping bag.

Finally, we check out two areas that were originally only found on mummy bags, but now crop up on many mainstream examples. The first is zip baffles, which prevent any cold air penetrating via the zip. The second is hoods: even the most basic – which are essentially just a short continuation of the bag’s base – provide a warm layer between your head and the (often cold) pillow. More advanced designs have draw cords to allow you to tighten the hood around your head, while others go further by locking heat into the main body of the bag, using drawstring-tightened baffles to grip around your shoulders.

Here we review the Outwell Campion, a sleeping bag that seems to have taken the best ideas from all other bags, from high-tech, extreme-temperature versions to traditional envelope types, and distilled them into one very versatile all-rounder.

From a high-tech perspective there’s a mummy-style hood complete with a drawstring, advanced, beautifully smooth materials that can withstand both machine-washing and tumble-drying, a compress bag for compact storage, as well as excellent thermal properties. But the traditional envelope shape allows for a more relaxed sleep than in pure mummy bags, and this is further aided by generous levels of roominess.

In fact, this sleeping bag impressed us so much that it was crowned the winner of the Practical Caravan sleeping bag group test. We also reviewed the high-tech Robens Trailhead 1500, Easy Camp Cosmos and the Musucbag Lite, all of which received four-star ratings.

The Coleman Vail Comfort rectangular sleeping bag looked pretty good at first, being roomy and warm, with superb thermal properties. £53 seemed a fair price for it, but then we realised that it’s pretty bulky to fit into your caravan locker by day and, worst of all, it’s not possible to machine wash and tumble dry it, hence the two-star rating.

The Vango Serenity sleeping bag, at £41, is a far better option for anyone wanting a rectangular sleeping bag, because again it has excellent thermal insulation and loads of space inside Better still, you can machine wash and tumble dry the Serenity. But it’s not a patch on the Outwell Campion.