I am looking at jackets like the the Rab Microlight, Patagonia Down Sweater, and Mountain Hardwear Nitrous. Many companies have similar designs all around 12oz with 4oz fill. What kind of warmth can I expect out of something like this? So far I am leaning towards the MH Nitrous because it is cut long and slim. Montbell has some insanely light down jackets but I am thinking they won't be quite as warm.

Edited by Bender on 12/10/2009 23:32:18 MST.

Bender,
Go here for a full answer

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=18950&skip_to_post=147100#147100

I showed up to Yosemite this Sep without a good jacket. The morning we were to head out, the meadows was hit with a sudden hail storm and then snow! so i grudgingly forked over the $180 for a Marmot Guide Down Sweater, (650fill goose down) and hit the trail. My first decent down jacket, I loved it.
I cant comment on the other brands, but this thing (with a base layer and warm fleece underneath) allowed me to sit out and watch the storm clouds put on a beautiful show at 10pm that night at 10'000ft. everyone else had tucked into their warm tents. I would have missed that without that jacket. the next morning i set out early at 6am to explore a lake with the same setup, i was not chilled at all in the 35 degree air.
Caveat: I am warm-blooded and tend to handle cold well.
I hope this helps you gauge.

A good one is very warm. I have a Marmot Zeus, and this is my second Wisconsin winter in it. I absolutely love it. I have a size medium, and it weighs about 15 ounces. Their website says 12 ounces, so mine may need a wash....

It may be a little heavier than some down sweaters you've seen, but considering that Marmot uses 1.1 oz yard (outer) and 1.8 oz yard (inner) material, this jacket has a lot more than 4 oz. of down fill. By my rough guess, I think the medium uses about a yard of each, for a total fabric weight of about 3 ounces. Add zippers and pockets and elastic, you're up to 4-5 ounces tops. That leaves about 7-8 ounces of fill.

(I have no proof of this, just guessing. If someone has hard numbers, please post them!)

The down is top quality, it zips up comfortably snug around your neck, which is important for minimizing heat loss. It also has an elastic hem drawstring, also for minimizing heat loss. This is now an essential feature for me on any coat I want to keep out the elements, or heat in, or both. It helps A LOT!!! It also stuffs into its own pocket.

It blocks wind very well, and with a warm sweater, will do fine with a minus 10 to -15 windchill. But thats me. YMMV. I've got no affiliation with Marmot, just love for this jacket! BTW, I have 4 marmot jackets. Love them all....

And if you get it from REI, you can try it out on a really cold day. If it doesn't keep you warm, you can return it. Just don't wear it half the winter and then return it. IMO, that's abusing their great return policy.

Side note....Waking up from a night's sleep and stepping into 15 degree air, even with ANY coat on will probably not feel as warm as running around the city doing errands midday, even at 10 degrees. But it'll warm up soon enough. All I'm saying is no piece of gear will perform the same in different situations.

Bender,

The following are the average camp chores comfort ranges for the jackets you are considering:

Rab Microlight 38 - 20
Patagonia Down Sweater 44 - 27
Mountain Hardwear Nitrous 43 - 27

The temperature ranges assume you are an average male, out of the wind, and wearing an average compliment of winter base layers under the jacket (1 clo).

Edited by richard295 on 12/11/2009 10:34:47 MST.

Having made my own insulated jacket and drawn the patterns for it I can give you some firmer numbers on shell weights.
First off, you're going to have, for a men's large, around 2 square yards of fabric for each layer (shell or lining). findings (zip, elastic, etc), will be likely 2 oz. So, with 1.1 and 1.8 oz fabrics, that gives you about 8 oz of shell, roughly.

Edited by paul on 12/11/2009 16:28:55 MST.

If you are willing to carry 11 or 12 oz, try this baby on for size - a step up from the jackets you mention

http://westernmountaineering.com/index.cfm?section=products&page=Down%20Garments&cat=Jackets%20and%20Vests&ContentId=55

i have the rei generator jacket

800 fill down had it in 31 deg temps with a long sleeve shirt on underneath it and was comfortably warm

temps dropped to around 27 in the evening so i put on a
columbia lightweight fleece under the jacket and roasted in it when i went outside
great jacket for the price and super warm to boot

divr6347

Edited by divr6347 on 12/11/2009 18:54:45 MST.

I have been wearing my TNF Thunder everyday this winter. We've had low's in the single digits here in Boulder. I've been warm just wearing my jacket and a hoody underneath it. May not be the lightest jacket, but I love it.

Paul--thanks for that info. I guess I was a little off. 2 yards of fabric for each layer is more than I thought! It just doesn't look like it, but as we all know, looks can be deceiving.

Eddie Bauer's new First Ascent line has a 900 fill (yes, 900!) down sweater/jacket. Limited edition. Just puttin' that out there.

anyone have comments on the montbell ex light with 900 down?

http://www.montbell.us/products/disp.php?cat_id=70&p_id=2301344

Wow lots of great info guys. I am impressed with the First Ascent Downlight. I didn't know Eddie Bauer made anything I would actually like. For $64 Lands End wins the cheap contest with its 700 FP SnowPack. The North Face thunder and OR Transcendent both look good. I generally like the cottage manufacturers for sleeping bags & tents but I haven't found a light down jacket from them I like. I will probably end up with the MH Nitrouse due to its fit and style.

The Montbell EX Light is crazy at 5.7oz but not quite in the same warmth category as the ones above. It would be the perfect Summer jacket especially since it packs down to nothing. I would love to have something like this in my bike bag. Why cant they just double the down and it would still be under 8oz!

i also have the thunder which is ridiculously light for the warmth it gives. i checked out MH's nitrous, but it appeared to not have as much loft as TNF did.

imo any 800 fill or greater, down sweater will be an excellent choice

If I didn't already have my TNF Thunder, I would definitely buy the First Ascent Down Sweater. If you like the fit of the MH, look at the First Ascent stuff. They also have long sizing for the 6'0 and above crowd.

Joe,

I have the Montbell Ex Light size L and it weighs 6.1 oz. Without any scientific test it seems just as warm as my Patagonia Down Sweater which weighs 11.7 ozs.

The Montbell shell seems very fragile, and I am constantly worried about tearing it or other damage. But it is the jacket I take on most trips.

Just as an aside, I would be skeptical of the 900 fill-power promises. Somewhere on the net there is a pod cast interview with the founder of Western Mountaineering and he discusses how some of these higher fill-power numbers are arrived at. I don't recall details but the down is subjected to conditions it would never encounter in a real world setting prior to measurement.

If there is anyone I would feel I could trust on the subject it would be someone from Western Mountaineering. In my opinion, any down claimed to be of higher quality than theirs or Feathered Friends is a bit grandiose. Not to say that it cannot be the same quality, but I doubt it exceeds the quality of those two manufacturers.

Apologies. I know that I am off topic.

+ 1 to Ty about 900 down skepticism

The strange thing about First Ascents 900 down is that it doesn't make the down sweater any lighter than their 800 down. Both versions are 13.4oz.

Just to throw another option at ye. Have you checked out the above PHD jacket/Pullover ? 900 fill, 230g (8oz for the Americans) and a typical operating temp of -5c (23f)

PHD are very highly regarded over here in Europe and the top may be worth a look.
http://www.phdesigns.co.uk/product_info.php?cat=110&products_id=240