Often regarded the preserve of climbers perched on inaccessible rocky ledges or soldiers hidden in the bushes, in the right conditions the bivvy (bivi, bivvi or bivouac) bag can add a whole new level of enjoyment to an overnight camp. They’re basically a waterproof cover for a sleeping bag, ideally made from a breathable fabric to reduce condensation build-up within, and sometimes fitted with a zip to make access easier. Combined with a sleeping bag and a ground mat (placed within the bivvy bag or left outside) the small footprint makes it possible to sleep in places where a tent would be unsuitable, be it on a rocky Munro summit or a location where stealth camping is required. With no door to form a barrier from the environment you can form a real connection with the surroundings – drifting off to sleep as the sun sets and waking to a star-studded sky or dawn temperature inversion. They’re generally lightweight (though there are options that use poles and are heavier than a one-man tent) and pack down small, and as we’ll discover below, they can be very cheap.
Disadvantages: if it rains it can be pretty unpleasant sealed inside a fabric coffin. There’s no room to get changed in privacy or cook. All your stuff has to stay outside. Midges. Think of the midges.
It isn’t for everyone, and for longer trips even bivvy-supremo Ronald Turnbull, author of The Book of the Bivvy, recommends seeking the sanctuary of a bothy or hostel with drying room every few days. But for one night? Give it a go.
In this review I’ll be looking at a range of bivvy bags from the budget (but stopping short of an orange plastic survival bag) to the premium, some little more than a sack, and some offering wired hoods and mesh windows.
Alpkit HunkaRRP £30
Probably the beginners’ bivvy bag, popularised by Alastair Humphreys as part of his Year of Microadventure campaign and at £30 providing an inexpensive introduction to the world of after-work adventuring. But this price tag doesn’t really do the product justice – the Hunka performs the basic function of weatherproofing a sleeping bag without any fuss or unnecessary accoutrements. The waterproof breathable PU coated nylon fabric is 2.5 layer (with a printed inner layer rather than the scrim found on more expensive 3 layer fabrics) and there is often condensation on the inner surface by morning, though this is significantly reduced if the drawstring hood is used effectively and breathing into the bag is avoided. Other than this drawstring – fitted with two cordlocks, one on each side of the opening – there are no other features, no zip entry, no mesh window, and this keeps the weight down to a respectable sub-400g. The stuffsack is even integrated into the base of the bag meaning there’s one less thing to lose on the hillside and packs it down to a small, rucksack friendly size. The regular Hunka is fine for a three-season sleeping bag and a thin self-inflating mat placed inside the bivvy, but as a broad six-footer I’d need to size up to the larger Hunka XL if using a thicker air mattress and/or a winter-weight sleeping bag to avoid insulation compression. For most people this is all the bivvy bag that they’ll need, so why pay more?
Fabric: PU coated nylon Weight: 376g
Snugpak Bivvi Bag RRP £65
UK manufacturer Snugpak supply equipment to the military so it’s no surprise that they have a bivvy bag offering, available in a choice of black, desert tan and olive green fabrics. It’s another low-priced and squaddie proof option, with a single cordlock cinch at the large opening – no zips to add weight or snag when leaving in a hurry. The Paratex fabric is waterproof and seems to resist condensation as well as other PU coated fabrics, but there is a notable difference in performance when compared to more expensive waterproof breathable fabrics. The 220cm length and 75cm width accomodates a three-season sleeping bag and mat and it packs down into a grapefruit-sized package in the supplied stuffsack. Simple and robust, supported by Snugpak’s reputation for no-nonsense UK-made outdoor equipment.
Fabric: Paratex Dry Weight: 340g
Rab Sierra BiviRRP £200
The bright orange 3 layer eVent fabric may be wonderfully breathable and comfortable thanks to the inner scrim layer, but it’s hardly stealthy! Thankfully an olive green model is available too. This is a refined bivvy bag, as you’d expect given the price, with a load of clever features that make bivvy life more pleasant. Firstly – it’s huge, easily accomodating an expedition sleeping bag and a thick air mat without compressing the insulation, and uses two fabrics, a durable 70 denier laminated nylon base with a 40D eVent upper. Entry is aided by a T-shaped waterproof zipped opening which extends down the chest and side to side across the shoulders. This can be tailored to offer just the right amount of venting according to sleeping position. Above the zips a wired peak keeps the fabric away from the face and a mesh window offers a view in bad weather while keeping the bugs at bay. This can be sealed with a popper if necessary. This all adds to the weight, and with tents now weighing under 1kg this isn’t the bivvy to choose if motivated purely by the weight saving. Instead, focus on the small footprint and the ability to camp on pretty much any person-sized area in relative comfort when compared to the less feature-laden options.
Fabric: eVent Weight: 750g
MSR AC BivyRRP £175
The AC Bivy uses lightweight 40 denier fabric all-round – a PU coated floor plus a proprietary waterproof breathable upper fabric (again, subtle bright yellow). This keeps the weight down but it’d be wise to place the sleeping mat outside to protect the base. The large mesh window is a nice feature, providing good visibility while repelling winged intruders. There isn’t a wired brim but a small webbing loop means the hood can be suspended from an overhanging tree or walking pole. There’s no way of securely closing-off this window in heavy rain, but using a bivvy bag in the rain is rarely fun anyway. Thankfully there is enough fabric in the cavernous hood to allow for a decent overlap and offer good living space. In fact, the overall dimensions are big; 91cm at the shoulders tapering down to 58cm at the foot box which is shaped to help reduce insulation compression. The cut is such that it’s actually possible to sit up and get changed within the bag without too much hassle.
Fabric: 2 layer waterproof breathable ripstop nylon Weight: 450g
Terra Nova Discovery BiviRRP £200
I suspect that the Gore-Tex fabric upper has raised the price of an otherwise simple bivvy bag – the 3 layer Gore-Tex Flo2 is breathable and rugged, but the base is non-breathable Waterbloc so side sleepers are going to have to be sure to turn within the bag rather than end up sleeping with the upper on the bottom. The non-waterproof shoulder zip is chunky with easy to use zip pulls (nobody wants to get trapped in a sealed bivvy bag) and protected with a large external storm flap. The cut is generous enough to be unrestrictive, and the hood is particularly large. There’s no mesh window or any other features and this simplicity is appealing, but unless a Gore-Tex bag is essential there are better options for less money and with a lower weight.
Fabric: Gore-Tex Flo2 Weight: 640g