How to Choose a Sleeping Bag | NZ Camping & Hiking Guide
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Sleeping bags get technical fast: fill power, temperature ratings, mummy versus rectangular, down versus synthetic. You can go deep down that rabbit hole, or you can pick a bag that suits the way you actually camp. Most people don't need expedition gear. They need a warm night's sleep and something that fits in the boot.
The quick answer For most New Zealand campers, a 3-season synthetic bag rated to around -5°C comfort is the safe pick: warm enough year-round, forgiving when it's damp, and good value. Going ultralight or alpine? That's where down earns its price.
First question: are you carrying it, or not?
This is the one that decides everything else. If you're hiking or tramping, weight and pack size matter, because every gram ends up on your back. If you're car camping, none of that really matters and comfort and price win instead.
A lot of people accidentally buy a hiking bag for car camping. It's a bit like wearing racing shoes to mow the lawn: nice gear, not really necessary. Start from how you'll carry it and the rest gets simple.
Down vs synthetic
This is the classic debate, and the honest answer is that each wins in a different situation. Here's the short version side by side.
| Down | Synthetic | |
|---|---|---|
| Warmth for weight | Best there is | Good, but heavier |
| Pack size | Packs very small | Bulkier |
| When wet | Loses warmth | Still insulates |
| Price | More expensive | Better value |
| Best for | Hiking, alpine, ultralight | Car camping, wet trips, budgets |
A soaked down bag is about as useful as a damp newspaper, which is why synthetic makes so much sense in a country as wet as ours. If weight is the whole game, though, down still can't be beaten. Browse the full range in sleeping bags.
Temperature ratings, minus the marketing
The number on the bag is usually closer to a "you won't freeze" rating than a "you'll be cosy all night" rating. Buy on the comfort rating, not the limit. If you feel the cold, size up in warmth: nobody ever complained about being too toasty.
| Rating | Good for | Typical use |
|---|---|---|
| +5°C | Warm summer nights | Coastal hikes, DOC campsites, beach missions |
| 0 to -5°C | Most of the year | 3-season tramping and camping |
| -9°C & below | Cold & alpine | Winter camps, high huts, snow |
Weight and pack size
Down bags compress small; synthetic bags take up more room. If the bag is riding in the boot, this barely matters. If it's going on your back for three days, it matters a lot. Match the bag to the trip, not the spec sheet.
What's your situation?
Not everyone buying a sleeping bag is heading up Everest. Pick the line that sounds most like you.
Multi-day alpine climbs
A lightweight, high-quality down bag. Warmth for weight is everything when it's all on your back. The Rab Ascent Pro 800 is built for exactly this.
Weekend tramping
A light synthetic or down bag depending on budget: warm enough for NZ nights, light enough that you don't resent it halfway up the hill. Start with hiking gear.
Summer camping
A light synthetic bag is usually perfect. Cheap, cheerful, and warm enough for DOC campsites and beach missions. See camping.
Kids' sleepovers
Almost anything works. Half the time the sleeping bag ends up being used as a pillow while they stay up eating sugar and watching movies anyway.
Summer festivals
Synthetic is a good call. Something you won't cry about if it ends up muddy, damp, or used as a couch at 3am. Grab something cheap and cheerful from camping.
Winter camping
You'll want a properly warm bag: a good synthetic winter bag or a down bag rated for the cold, like the Rab Ascent Pro 800 Long. Cold nights are great right up until you try to sleep through one.
Banished to the couch
Any sleeping bag will do. Preferably one that lets you maintain some dignity while pretending you chose to sleep there.
The short version
- Hiking: lightweight down or quality synthetic
- Car camping: synthetic is great value
- Cold conditions: choose warmer than you think
- Wet environments: synthetic is more forgiving
Are these your bag?
Sleeping bag FAQs
What sleeping bag do I need for NZ camping?
A 3-season bag rated to 0°C or -5°C covers most NZ conditions year-round. If you're only camping in summer at low altitude (Abel Tasman, coastal hikes), a +5°C bag is enough and packs down smaller.
Is down or synthetic better for New Zealand?
Synthetic, for most people. NZ is wet, and synthetic fills keep some warmth when damp and dry faster. If you're doing serious alpine tramping where weight matters, get a hydrophobic down bag. For everyone else, synthetic is more practical and costs less.
What does a -5°C comfort rating actually mean?
A typical adult will sleep comfortably at -5°C. The limit rating is lower: the temperature a cold sleeper could survive without hypothermia. Buy on the comfort rating, not the limit.
Can I use a liner instead of buying a warmer bag?
Yes. A fleece liner adds 5–8°C of warmth to an existing bag for a fraction of the price. If you already have a bag and only need a bit more warmth, a liner is the better move.
Is last season's sleeping bag as good as this season's?
Yes. Insulation tech doesn't change year to year. A -5°C bag from last season is exactly as warm as the same rating this season. You're paying less because a new model came out, not because the bag got worse.
How do I look after my sleeping bag?
Store it uncompressed (in a large sack or hung up), not stuffed in its stuff sack. Wash it a couple of times a year on a gentle front-loader cycle with detergent made for down or synthetic.
