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PHD Design Your Own Sleeping Bag

Chris Townsend walks us through the PHD Design Your Own Bag feature online.

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by Chris Townsend | 2008-11-04 00:05:00-07

Off the shelf gear is never perfect, unless you're that mythical "average" size. Even then, there may be features you don't want and ones missing that you would like. Ideally, all gear would be custom made to exact requirements. Of course, you can make it yourself, and many people do this. For most of us, though, this isn't an option, especially with complex items like down sleeping bags. Many companies offer options in length and sometimes width, with a variety of features available. But finding a bag the right size with just the features you want, no more or less, can still be difficult. Enter British company PHD and its Design Your Own Sleeping Bag online program. This offers a huge array of options (at least seventeen, depending on the basic style) and is well-designed and easy to use. The bags use the latest, lightest materials and top quality down.

Using this feature, I designed a bag which PHD then made for me. Below, I describe how the process went, what the resulting bag is like, and how it performs. PHD uses metric measurements throughout, and I have followed this. You will need to be familiar with metric weights and measures to use the facility or else have a calculator handy.


PHD is a small, specialist down sleeping bag and clothing company based in northern England, where all the products are made. PHD stands for Pete Hutchinson Designs. Founder and owner Pete Hutchinson has been involved in producing top quality down gear for mountaineering and polar expeditions, including many to Everest, since the 1960s (he founded the UK company Mountain Equipment in the 1970s). PHD's standard sleeping bags are excellent - I've used several of them in recent years, especially the ultralight +5 C/41 F rated 16 ounce/465 gram Minim and the -5 C/+23 F rated 24 ounce/670 gram Minimus.

Choosing the Route

The process starts on the main PHD web page, where you click on the 'Design Your Own Sleeping Bag' box at the top of their home page. This takes you to an intro page with a dramatic snowy mountain scene, accompanied by the sound of a rushing chill-inducing wind and some atmospheric flute music. This only lasts seconds but can be skipped. This leads into the opening page, which tells you that there are two design routes, a free route for the experienced, who have used sleeping bags and understand their design, and a guided route for those who need assistance.

PHD Design Your Own Sleeping Bag - 1
The opening Design Your Own Bag page.

PHD Design Your Own Sleeping Bag - 2
The first choice: free or guided?

The Guided Route

Select the Guided Route and a page opens to enter the minimum temperature you expect to the bag to handle. This brings up a selection of PHD bags close to that rating. Change the temperature and the selection changes. The weight and price of the bags are given, along with their categorization as ultralight, which means few features, or hi-tech, which means many features. Continuing in the Guided Route allows you to modify these standard designs. Click on one of the bags and a page comes up with information and details. Click on 'Choose This Bag' and the actual design page appears with all the options. These also appear in the Free Route and are described below. In the case of the Minim 400 sleeping bag I chose for this example, after entering -5 C, I added some features which raised the weight and price. It is always possible to go back and change your design if it's not working out as you wish, and you should review the design before submitting an order.

PHD Design Your Own Sleeping Bag - 3
The Guided Route starts with minimum temperature selection.

PHD Design Your Own Sleeping Bag - 4
Having selected a bag, the Guided Route provides the details.

PHD Design Your Own Sleeping Bag - 5
Now the chosen bag can be modified to fit your requirements.

PHD Design Your Own Sleeping Bag - 6
My choices in the Guided Bag Route added 105 grams to the weight and £70 to the cost. I selected a lighter shell fabric, but added a short zip, a collar and waterproof panels in the hood and at the feet.

The Free Route

The Free Route is the one to choose if you know the type of bag you want and don't want to be restricted to modifying an existing PHD bag. The first decision to be made is whether you want a lightweight style or hi-tech style bag. Full details of each are provided. The lightweight style is a simple design with an open hood (which means a zipper isn't essential) and box wall baffles. The high-tech style has trapezoidal baffles, vertical channels over the chest, side channels and a close-fitting mummy hood that doesn't open wide. PHD says hi-tech bags are for extreme expedition use and high altitudes. For most backpackers the extra weight of a high-tech bag is probably not justified. I certainly wanted the lightest bag possible for the minimum temperature rating and so chose the lightweight option. As an exercise, I also designed a hi-tech bag with the same fill and shell fabrics as the lightweight bag described below. It weighed 364 grams more and cost £83 more, both substantial increases, but the minimum rating was the same.

PHD Design Your Own Sleeping Bag - 7
Lightweight or Hi-Tech? The first choice on the Free Route.

Once a choice has been made between lightweight and hi-tech, the next decision is the amount and quality of the down. The possible quantity of down runs from 200 to 1300 grams in 50 gram increments and 700, 800 and 900 fill power down is available. If you're not sure what the differences between these are, or how much down you need, you can click on 'view important information about this option,' and a pop-up chart appears showing you the temperature ratings for different quantities and qualities of down. Bags can be designed with minimum temperature ratings from +7 C/45 F to an astonishingly cold -64 C/-83 F. Sensible warnings point out that this is only a rough guide and that many factors need to be taken into account, both subjective (metabolism, tiredness, food and drink) and objective (humidity, wind, sleeping pad, clothing, altitude). I wanted a bag that would keep me warm down to around -5 C. The 400 grams of 800 fill power down had this rating but the same amount of 900 fill power down had a -8 C rating. That little extra touch of warmth with no increase in weight sounded appealing, so I chose the 900. No choice is fixed however; you can always change it later on in light of the weight, cost, or temperature rating of the bag.

PHD Design Your Own Sleeping Bag - 8
Choosing the down.

PHD Design Your Own Sleeping Bag - 9
Insulation Quantity/Maximum Temperature chart.

Once the quantity and quality of the down has been chosen, you move onto choosing the details. The next page shows the basic bag with the price, weight, and temperature rating. Each time you make a decision that affects any of these, they change so you can keep a precise track of them and go back if necessary. There are seventeen different options covering outer and inner fabrics, color, stuff pattern, zippers, hood, down fill power and weight, down overfill, collar, inner panels, side baffles, hood and collar cords, bivvy cowl, length, and width. With all these options, there are explanations and definitions to help with your decisions. The number of permutations is enormous and fun can be had changing them and watching how the weight, temperature rating, and price change. Here's a rundown of the options, their usefulness, which ones I chose, and why.

PHD Design Your Own Sleeping Bag - 10
Inputting the design.


Four shell fabrics are available. M1 is a microfiber weighing 42 grams per square meter (g/m2). MX is an ultralight ripstop nylon weighing 30 g/m2. Both are highly breathable, downproof, wind resistant, and fast drying. Drishell is 48 g/m2 ripstop nylon with an ultralight coating. The seams aren't waterproof, but the fabric is water resistant, and it's still very breathable. The fourth choice is 70 g/m2 Gore-Tex with fully taped seams. This shell is fully waterproof and lowers the bag's minimum temperature rating to -13 C, but it also adds considerable weight, (the bag weighing 870 grams as opposed to 640 grams for one with an MX shell) and price (£381 as opposed to £259 for the MX). The Drishell outer would be a good choice for use with tarps in damp climates. The Gore-Tex shell might be useful on polar expeditions or alpine climbing, but is too heavy for backpacking, in my opinion.

I prefer highly breathable ultralight sleeping bag shells so the down can loft fully and body moisture can escape quickly, so I chose the MX shell, as it's the lightest. I rely on my shelter, whether bivvy bag, tarp, or tent, to keep off rain.

The choices for inner fabric are MI, MX, Drishell, and 54 g/m2 Pertex, which is the least expensive, but also the heaviest fabric. Again I chose MX.


The choice in colors is not great. Drishell has most with four - red, black, blue, and gold. For M1 and Gore-Tex, the choice is red or black. For MX and Pertex it's the old Henry Ford choice - black, black, or black. Luckily, I like black for sleeping bags, as it absorbs heat and dries fast when aired in the sun.

Stuff Pattern

This is an interesting option that allows you to have the down redistributed so there is more on the top, base, or foot of the bag. In a standard PHD bag, the down is distributed almost equally, with just marginally more over the chest and at the foot. Obviously if you have more down in one area there will be less everywhere else, reducing the overall warmth of the bag (PHD doesn't say how much down is redistributed). However, if you suffer from cold feet (a common complaint) or a cold chest, then having more down in the foot or on top could be useful. If choosing this option, I would start with a bag rated for colder temperatures than I expected so that even with less down in some areas it should still be warm enough. However, as I don't generally feel particularly cold in any one area, I chose the standard stuff pattern.


Zips can be on the right or left side, long or short, with single or double draft tubes. I was interested to see just how much weight a zip and draft tube adds - 150 grams for full length zip with double draft tube, 120 grams for full length zip with single draft tube, 65 grams for short zip with double draft tube and 55 grams for short zip with single draft tube. I avoided any extra weight by opting for no zip at all. This reduces ventilation options, but that's not something I've ever found to be a big problem.


The choice is between an open hood, which can be tightened around the head when needed but which allows good ventilation when fully open, and a mummy hood, which always fits close round the face. The bag has to have a zip to have a mummy hood, so I'd have had to go back and choose a zip if I wanted one. I prefer an open hood anyway, as it's more versatile.

Down Overfill

After confirming or changing the amount and quality of the down, there's an option for putting extra down into the shell so the down is packed more tightly. PHD points out that they optimize the amount of fill and the shell size, and that an overfilled shell doesn't have as good a warmth to weight ratio, but some people like a thicker feeling bag, and it reduces the chance of thin areas appearing due to the down shifting as you move in the bag. A better warmth to weight ratio can be had by increasing the standard amount of down in the previous step or the quality if 700 or 800 fill power down has been chosen. The amount of down overfill is 100 grams. If chosen this would have lowered the minimum temperature rating of my bag from -8 C to -11 C. However, if I'd increased the amount of down by 100 grams and had a shell sized to go with this, the rating would have been -14 C at a weight increase of 15 grams over the overfilled bag.


This is a simple option: to have a collar or not. I chose not, as one adds 60 grams of weight, and I don't like collars much anyway, as they restrict ventilation and don't seem to make much difference in warmth.

Inner Panels

Water resistant panels in the hood and the foot can protect the down against moisture from your breath or dampness from socks. I've used bags with these, and they do work, especially the one in the hood. I haven't had serious problems without them however. PHD's Drishell panels only added 10 grams (and £15 in cost) so it was tempting to add them. However I wanted the lightest bag for the warmth, so I resisted.

Side Baffles

Side baffles prevent the down from shifting from top to bottom and vice versa. In bags without them, you can shift down from one side to the other to increase or decrease the warmth. If, that is, you can keep that side on top. Those who turn in their sleep and often wake with the bottom of the bag on top, as I do, learn that no side baffles can mean waking in the early hours with a cold back as the down has shifted. That is my one complaint with PHD's off the shelf ultralight bags - they don't have side baffles - and a main reason why this design option is of value to me. So I chose the side baffles, despite the 10 gram weight increase - my only concession to a feature that added weight.

Hood and Collar Cords

The choice here is between stretch and non-stretch. Having used both, I find non-stretch hood cords easier to use and less likely to allow the hood to gape, letting in cold air. If I'd chosen a collar, I'd have gone for a stretch cord, as these give when you move, making them less restrictive than collars with non-stretch cords.

Bivvy Cowl

This is a curious option that is basically the top half of a bivvy bag. It's made from proofed nylon and lies under the bag when not needed. Pulled up it covers the head and body down to the chest. There's an elastic drawcord in the hem but no zip. The seams aren't sealed, so it's not fully waterproof. PHD says it's for below freezing conditions, not rain. In combination with a bag with a waterproof shell, I guess you could sit out a blizzard on a ledge during a climb with this, but I don't think it's of great interest for backpacking. It adds 100 grams to the weight and £37 to the cost.

Length and Width

Being able to choose from five lengths and four widths is one of the great benefits of PHD's Design Your Own Bag, as many people find the choices in off the shelf bags too limited and end up with bags that are too long, too short, too wide or too narrow. In lightweight bags, PHD offers lengths for people up to 142 centimeters/62 inches (X-Short), 168 centimeters/66 inches (Short), 183 centimeters/72 inches (Standard), 198 centimeters/78 inches (Long) and 213 centimeters/84 inches (X-Long). Being 5'8", I chose the Standard length. The widths refer to the maximum torso circumference, whether the chest or waist. The options are up to 92 centimeters/36 inches (Slim), 109 centimeters/43 inches (Standard), 121 centimeters/48 inches (Wide) and 135 centimeters/53 inches (X-Wide). Again, I chose the Standard width. (For some reason, PHD gives English and metric measurements here).

The Final Decision

Once all the decisions have been made and perhaps considered and reconsidered, you can review the bag you have designed and submit your order. Before doing this, you can save a copy of your design and email it to yourself as well. This is done by clicking on the floppy disc image in the lower left corner of the sleeping bag picture. This saves the design and brings up a box in which you can enter your email address and then click to have the design emailed to you. I did this and a few minutes later received an email containing the following:

Your Bag Design

Bag Name/Type: Lightweight
Price (£): 268
Weight (g): 650
Min Temp C: -8
Outer: mx
Inner: mx
Down Fill (g): 400
Down Quality: 900
Down Overfill: no
Stuff Pattern: std
Zip: none
Length: std
Width: std
Mummy: no
Collar: no
Inner Panel: no
Side Baffles: yes
Hood Cord: nonstretch
Collar Cord: none
Bivvy Cowl: no
Outer Color: black
Inner Color: black

PHD Design Your Own Sleeping Bag - 11
Checking the final design.


PHD gives deliver time as twenty-one days in the UK, thirty days outside the UK. Mailing charges are £15 for the UK and the EU and £25 for other countries. My bag arrived in a week, but it was a special order for this article.

The Sleeping Bag

Of course, for the application to be really useful, the end product - the sleeping bag itself - has to fit the design brief. The bag supplied does this perfectly. The dimensions are correct and the weight is 652 grams/23 ounces. The fit is on the slim side, but there is enough room for me to move in the bag and to wear clothing if necessary. The MX fabric is very soft and comfortable, and the bag feels luxurious to sleep in.

PHD Design Your Own Sleeping Bag - 12
The finished bag.

The bag is supplied with a stuffsack weighing 25 grams/0.88 ounces and a big mesh storage bag. The stuffsack measures 30.5 centimeters/12 inches by 18 centimeters/7 inches, which is quite compact for a bag with this rating. It can be compressed to half this size. The stuffsack isn't waterproof, so in wet weather, it will need to be stored in a waterproof pack liner or replaced with a waterproof stuffsack (or both if you want to be really certain it'll stay dry in the pack).

PHD Design Your Own Sleeping Bag - 13
Weight of the bag with stuffsack.

PHD Design Your Own Sleeping Bag - 14
The stuffed bag compared to a 750ml titanium mug.

I haven't yet been able to sleep in the bag at -8 C/17.6 F, as early autumn temperatures in Scotland do not often dip below freezing. At +5 C/41 F, I was very warm with the hood wide open.

Comparable with the PHD bag is Rab's Quantum 400, one of my favorite bags, which weighs 885 grams/31.2 ounces and costs £250. The Quantum 400 has 400 grams/14.1 ounces of 750 fill power down (European measurement)/850 fill power down (American measurement), and is rated to -5 C/23 F. PHD uses the European fill power measurement. However despite the theoretically higher lofting down in the PHD, I measured the loft of both bags as 13 centimeters/5 inches at the chest. The Quantum 400 has a full length zip with a baffle and a collar. If I'd chosen these features for the PHD bag, it would have weighed 830 grams/29.3 ounces and cost £304, still lower in weight but significantly more expensive. The Quantum 400 is slightly longer than the PHD at 215 centimeters/84.6 inches as opposed to 210 centimeters/82.7 inches. The Quantum 400 has kept me warm at -7 C/19.4 F, so I expect the PHD bag to do the same.

The Process Summed Up

The Design Your Own Bag application is easy, quick, and fun to use. All the options are clearly explained, as are the relationships between them when necessary (such as having to have a zipper with a mummy hood). Being able to see how changes affect the weight, temperature rating, and price of the bag, plus the choices you have made, means you are always fully in control of the process and can change any option at any point. This is a very well-designed program. Of course there are many good off the shelf sleeping bags, including those from PHD, and most people find one of these fine. However Design Your Bag provides the opportunity for a customized bag that is exactly what you want and which can solve problems of size for those who don't fit off the shelf bags. I think it's excellent.


"PHD Design Your Own Sleeping Bag," by Chris Townsend. (ISSN 1537-0364)., 2008-11-04 00:05:00-07.


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PHD Design Your Own Sleeping Bag
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Addie Bedford
(addiebedford) - MLife

Locale: Montana
PHD Design Your Own Sleeping Bag on 11/04/2008 19:55:17 MST Print View

Companion forum thread to:

PHD Design Your Own Sleeping Bag

cameron eibl
(cjeibl) - F

Locale: San Diego
- on 11/04/2008 22:38:59 MST Print View


Edited by cjeibl on 11/05/2008 08:57:54 MST.

Adam Kilpatrick
(oysters) - MLife

Locale: South Australia
Re: Minim 400 on 11/05/2008 02:28:20 MST Print View

why not go to the PHD website and try it yourself then?

Adrian B
(adrianb) - MLife

Locale: Auckland, New Zealand
Re: PHD Design Your Own Sleeping Bag on 11/05/2008 12:41:00 MST Print View

It's a pity that amongst all the options there isn't a hoodless bag, for use together with a hooded insulated jacket.

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Re: PHD Design Your Own Sleeping Bag on 11/05/2008 15:18:05 MST Print View

>It's a pity that amongst all the options there isn't a hoodless bag, for use together with a hooded insulated jacket.

True, it's not a completely customisable bag design, but I wonder how much extra weight does a hood add? Most of the time I don't even use my hood, but it doesn't get in the way of anything I do in my sleep...Of course, if you REALLY didn't want a hood you could always just cut it off and sew off the seam!

They also don't seem to offer a "topbag" design where the bottom of the bag is just a single layer of fabric with no down insulation. Those are my favourite bags.

I have a PhD Minimus pullover, and can attest to the great craftmanship of these products.

Dave -
(FamilyGuy) - F

Locale: Up there
PHD Design Your Own Sleeping Bag on 11/05/2008 17:40:25 MST Print View


Edited by FamilyGuy on 11/29/2013 17:48:33 MST.

Adam Kilpatrick
(oysters) - MLife

Locale: South Australia
PHD hoodless... on 11/06/2008 00:04:16 MST Print View

I reckon if you asked, PHD would do you a custom without a hood. They were willing to modify sizes of bags quite out of what they normally do for me (I asked them directly...I was thinking of getting one of their standard bags in a different size, and they promised to do it for the same price. Then I had to pay my student fees, haha). Making it hoodless would be a piece of cake for them.

Not sure about a top bag though...maybe we need to put the pressure on?

Jeff Piper

Locale: San Francisco Bay Area
Why not go with a Western Mountaineering bag? on 11/07/2008 20:34:42 MST Print View

How would something like this compare to a comperable Western Mountaineering bag? Seems like the expense, wait (and weight) just don't justify the bag. Any thoughts on this?

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Why not go with a Western Mountaineering bag? on 11/08/2008 11:37:37 MST Print View

>How would something like this compare to a comperable Western Mountaineering bag?

If you lived in the UK/Europe, the shipping and duties may be a consideration.

Ken Helwig
(kennyhel77) - MLife

Locale: Scotts Valley CA via San Jose, CA
Re: Re: Why not go with a Western Mountaineering bag? on 11/08/2008 12:08:57 MST Print View

Own three WM bags and will never own anything else. 'Nuff said.

Jason Brinkman
(jbrinkmanboi) - MLife

Locale: Idaho
Re: Why not go with a ... bag? on 11/10/2008 22:17:47 MST Print View

This is a great concept, and I enjoyed reading about it, but the exchange rate would have to be a LOT better before this would be worthwhile for me. And can't you already get a semi-custom bag from WM or FF?

Tim Kropf
(tkoutdoor) - F

Locale: Pacific Northwest
Re: Re: PHD Design Your Own Sleeping Bag on 11/11/2008 11:33:21 MST Print View

>It's a pity that amongst all the options there isn't a hoodless bag, for use together with a hooded insulated jacket.<

It sounds like you're describing a bag that I have already!

I've been very happy with my brief testing of my new Golite Ultra 20. It weighs 19 oz, rated for 20 degrees F. It's a variable girth quilt without a bottom. It has a sewn footbox and a snap for around the neck, but it has no hood like a mummy bag has. The website shows a sleeping pad being inserted inside the bag over the straps to form the bottom, but I've always used it directly over a pad with the pad outside the straps. My testing has only been down to 41 degrees so far and I was toasty in minimal clothing, but I'll get some time to test it in freezing and sub-freezing still this fall. Here's a link: The bag was pretty affordable at $225 U.S. as well.

I should be able to couple that with my Western Mountaineering Phantom 32 for some pretty low temps with a combined weight of about 2 lbs 9 oz in a couple of small packages. I'm thinking this way mainly because I already have both of them, I'm sure there's a more efficient system out there.

Edited by tkoutdoor on 11/11/2008 11:35:00 MST.

Charles Kukla
(charleskukla) - F
PHD Design on 11/17/2008 09:20:02 MST Print View

I have been using my PHD designed bag for several years and also have the minimus bag.

I designed the bag as a 0F bag and use the Minimus bag as an insert to extend the range to -20F.

The combination allows me to adjust my kit more precisely to the conditions.

The process was a great learning experience for me because it helped me to understand how to put really light kits together to fit the conditions.

The bag I designed is bright yellow which is really nice for early morning winter starts as the tent lights up with my headlamp and the light color allows me to use the bag as a platform to organize my gear. The stuff sack is short with a wide opening so that it fits easily into my backpack. It takes me about 50 seconds to stuff the bag and put it in the backpack.

Other bags I know are also of high quality but in this case I get to choose those design options that are most appropriate for me.

The quality is excellent. Lastly, the fleece products like the Taiga and the balaclava are also well designed and made.

Andy Howell
PHD on 11/23/2008 14:58:13 MST Print View

PHD produce great products. I use the standard range rather than the custom stuff. I guess there reason there is no hoodless version is that P{HD is in Britain. Mostly we need a hood!

Diplomatic Mike

Locale: Under a bush in Scotland
PHD Design your own bag on 11/23/2008 15:09:14 MST Print View

I prefer a hoodless quilt myself Andy. I've been using a Nunatak Arc Specialist most of this year. I've e-mailed PHD to see if they will make me one to my specs.

Martin Rye
(rye1966) - F

Locale: UK
Re: PHD Design your own bag on 11/23/2008 15:55:20 MST Print View

Mike do you use it inside a bivy bag? Lots folks do and that adds warmth and stops drafts etc. I wonder how warm quilts are in cold weather with out a hood and not used in a bivy bag. On PHD kit. I have a down jacket made by them and can not fault it. I have seen comments on poor finishing and customer service from others in the past. They are pushing the bounds a lot with 900 fill power and designs. PTC on his blog tonight said he has a lot to say about PHD kit from his snowy trip in the hills this weekend. Lets see if he comments here.

John Haley
(Quoddy) - F

Locale: New York/Vermont Border
Re: PHD Design your own bag on 11/23/2008 16:05:17 MST Print View

From the answers I received from Peter Hutchinson to all the questions I had about modifications it sounded to me as if PHD would modify to just about whatever is wanted.

Diplomatic Mike

Locale: Under a bush in Scotland
PHD Design your own bag on 11/23/2008 16:37:44 MST Print View

Hi Martin,
Sometimes i use a bivvy-bag, sometimes i don't. Depends on the conditions, and wether i'm in a tent or a tarp.
Depending on temps, i'll wear a hat or my Nunatak Skaha Plus down pullover. As someone said above, with a seperate hood/hat, you don't end up with a face full of sleeping bag hood when you turn over.
I love the quilt and have been toasty down to about -3C this year in a tent. I think it will do me for a lot lower temps.
I would need more insulation under a tarp, i think. That's why i e-mailed PHD. I would like a warmer quilt, made to my specs. The exchange rate has made it prohibitive to go back to Nunatak at this moment in time! :)

Martin Rye
(rye1966) - F

Locale: UK
Re: PHD Design your own bag on 11/23/2008 16:44:23 MST Print View

Sounds a good set up Mike. I wonder if PHD will make them as a stock item? PS check your email and Andy's blog and I think it will clear up that misunderstanding.