PHD Minim 400 K Series Sleeping Bag review

Last updated: 16-Aug-18

By Fiona Outdoors

An expensive but, at some point, useful outlay for ultra and marathon runners is a lightweight sleeping bag. It might be an essential kit list item for a multi-day race or something you plan to use on overnights during longer training runs. It needs to be light so that is can be easily carried in a rucksack, but it also needs to be warm so that you can sleep well.

Of course, the type of bag you buy will depend on when and where you will be using it. Most sleeping bags are rated according to their ability to keep the average person warm in a particular air temperature range. If you are prone to being cold, ensure you take this into account when choosing the bag.

The PHD K Series aims to “take warmth-for-weight performance to the limit of what’s possible”. PHD state that the K Series is made with “unique 1000 down, super-light materials and specific design features”.

The Minim bag is “minimalist”. So it’s a no-frills style of bag without a zip or collar.

PHD says: “Our extraordinary 1000 down ensures the performance, while the 10X inner helps to bring the total bag weight right down to a remarkable 585gm. The bag has a hood and box-wall construction throughout.”

PHD Minim 400 K Series Sleeping Bag – Features

  • -5°C (23°F)
  • 605g (21oz)
  • Range of different lengths
  • Range of different widths
  • 1000 Fillpower Down
  • Downproof and water-resistant Ultrashell outer fabric
  • No zip but an open hood to keep the weight down
  • Pack size: 17cm x 28cm
  • Price: £416
  • See PHD

If you are wondering, PHD stands for Peter Hutchinson Designs.

Photo credit: Fiona Russell.

Pros: What’s good about PHD Minim 400 K Series Sleeping Bag

The first thing that struck me about PHD is the desire to ensure you have the right bag. They ask a lot of questions about what you want and need in a sleeping bag. If they can find one that is ready-made (and therefore cheaper) they will but if not they can custom-make the perfect bag for you. See Design Your Own Bag.

They suggested, for example, that because I usually get quite chilly that I should use the Minim 400 K in temperatures around 0ºC to 5ºC, rather than pushing my luck in temperatures below zero.

I also liked what I read about PHD. Their website states: “We make everything, start to finish, in our own factory in the UK. Local people using traditional skills. It’s not as cheap or as efficient as large-scale production in the Far East or Eastern Europe. But we feel there’s a value in preserving and using the very real skill base which still remains in UK.”

The attention to detail is impressive. Read about PHD down, for example. The 1000 Fillpower Down is European goose down that PHD says is “of unique quality”. They add: “1000 provides the highest warmth-for-weight performance possible from down”.

If you want, you can also order fabric samples and pay only the postage, so you can see the quality before making a full purchase. The standard bag comes with an outer of MX Fabric. For an extra £20, I chose a DWR treated water-resistant Ultrashell fabric because I find that condensation can be a problem when sleeping in a tent on a chilly night.

The Minim 400 K bag is impressively light. It weighs only 100g more a bag of sugar.

I have slept in lighter bags but always ended up with a very cold night’s sleep, which has meant I’ve had to buy another bag or double up with two bags (thus negating the advantages of one lightweight bag).

So, as I set off into the hills with this PHD bag I was quite worried about the warmth. (I confess I had an extra “sleeping blanket” with me just in case I ended up too chilly.)

I have tested this bag on several occasions and in late summer and autumn in Scotland. The temperate on each occasion was around 5ºC and possibly dipped to nearer to 2ºC in the middle of the night.

I also tend to wear a few layers when sleeping. I wore walking socks, running tights and a long-sleeve baselayer top. The hood has a basic drawstring and toggle so you can draw it close around your head.

I’d asked for a width of bag that would give me some wriggle room. I don’t like to feel hemmed in by a bag and I usually want to move around inside the bag to turn over at night. I also like room to easily fit in my arms and shoulders and I sleep curled up so I need a bit of extra width.

I guess I am adding a small amount of weight to the bag by having a larger width but I am small anyway so it doesn’t make for a heavy PHD bag. PHD sent me a “standard width” for wriggle room because I am a slim female.

There is no wastage in terms of extra bag. You ask for a good fit and that is what PHD sends you.

Getting into the bag felt amazing luxurious. Although the bag is light it is also cosy. I would describe the outer fabric as being similar to parachute material and so it feels silky on your body. Although super light, the fabric also feels robust.

Once inside the bag I felt almost immediately warm and I stayed that way all night. Even my feet remained warm. At some points I felt a little over-heated but I’d prefer that than to be shivering.

I slept on one of the new style of super warm and comfortable Therm-a-Rest self-inflating mattresses. I used a spare down jacket stuffed into the sleeping  bag’s stuff bag as a pillow.

The bag did feel a bit damp the next morning (there were two of us breathing in the tent all night) but the down remained warm. Thanks to the DWR treatment the damp did not penetrate through to the down.

The bag stuffs down to an impressively small and lightweight sized stuff bag. In fact, it’s one of the most amazing things about this bag: It’s small and light yet plumps up to be nicely warming for summer/early autumn camping.

Cons: What’s not so good about PHD Minim 400 K Series Sleeping Bag

I missed having a zip. This bag keeps the weight down by having no zip at all, not even a small zip at the top. This means you have to wriggle into it. I had asked for a wider bag, fortunately, and this allowed me easier access to the bag but you do need to slot yourself in.

Getting out is a bit trickier. Once I’d drawn the hood around my head I had to wriggle a lot to get the bag off. This isn’t so easy when it’s dark in the middle of the night and there is someone sleeping next to you.

It’s also worth remembering that if a bag does not have a zip you cannot open it up for better ventilation or cooling if you are hot in the night.

I guess, you have to decide if you want to sacrifice features and extra “wriggle room” width and length for weight. If you are buying a bag for a race then lightweight is very important but if you are happy to carry a few extra grams and have a bit more comfort in the bag then choose a slightly larger fit.

This bag would definitely not be good for me on a night when temperatures dip to 0ºC or less so in the UK it would not work for around half of the year. It’s important to choose the right bag to suit the temperature and your own personal needs.

This bag is also pricey. For a no-frills bag, just over £400 seems like a lot to pay but, then again, the quality is superb and I like that it’s UK-made by UK people. I guess that you are paying for a greater ethical quality.


PHD make very good quality bags and in terms of weight-to-warmth I have not come across another bag that gets the balance so perfectly right. I like that the bags can be chosen to fit your exact size, rather than-size-fits-all. You pay more than other brands for the design, manufacture and materials but if super lightweight and warm are must-haves, this is a great bag to choose for nights that are cold but not super cold.

Design 9/10
Features 7/10
Performance 10/10
Value 8/10
Total 8.5/10


Other sleeping bags you may want to consider:

PHD Minimus Down sleeping bag
Mountain Hardwear HyperLamina Spark
Mountain Hardwear Phantom
Alpkit PipeDream 400 down sleeping bag

About the writer: Fiona is a keen runner, preferring off-road and hilly to flat and road. She lives in Scotland where the weather is fickle so needs to be prepared for all conditions.

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"If you want, you can also order fabric samples and pay only the postage, so you can see the quality before making a full purchase"

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