Down Bag rating inflation over the years?

I wonder how fill quality would change the specs? And overall weight for the two bags?

I do know this—When I got my WM Puma bag in 2005 it was rated at -15F at around 3 lbs 4 ozs. Now the same bag with the same weight is rated -25F. Very weird.

Tipi, at one point people considered western mountaineering to be too conservative with their ratings. They changed their ratings. That is what I heard.

Although the short answer IMHO is "yes", obviously it's a complex subject, and one would need to be sure they are comparing "apples" to "apples".

Newer bags tend to have 800 – 900 fp; older (mass market) bags often had 650 fp, which is loftier but heavier and less compressible. It would be nice to compare fill weight, but bags with different dimensions make doing that irrelevant.

Do *most* manufacturers rate (and measure) their bags optimistically? Yes, yes, yes in my opinion, with Western Mountaineering, Feathered Friends, and maybe another being the exception. I am now the proud owner of two WM bags, and although I'm a classic female "cold" sleeper, I feel that both bags' ratings are within 10F of how they "feel" to me.

I would not say the same for bags I've owned made by Marmot, Mountain Hardwear, and TNF (which is why I only own WM now!).

Recently, people have been switching to EN 13537 rating for sleeping bags. Scientifically based. A 0 degree bag should be good down to 0 degrees for an average person (although there are still differences between people). You can compare bags of different manufacruers.

Before this, manufacturers were more optimisitic and there was more variation between manufacturers. If one rates a bag as 0 degrees, but another rates the same bag at -10 degrees, they will probably sell more so there was a lot of pressure to be optimistic.

So, in that sense, ratings have been deflated in the last few years, and should remain constant as long as they continue EN rating.

The loft is an imperfect measure of warmth. Mainly, down requires more thickness to provide the same warmth as synthetic. But, it's a lot less dense so warmth per weight is a lot less. Also, you can put more down in the same baffles without increasing the loft, and it will still be warmer. I don't know if there's a difference between different fill powers and loft required to get the same warmth – it may be that higher fill power actually requires more loft to get the same warmth. And after you've used a bag and it's absorbed oil or whatever, it may require more loft to get the same warmth.

But, I would think if two down bags had the same loft, they would probably provide about the same warmth.

It's hard to say for certain, but i suspect that Valerie is correct, that the older bag possibly uses a lower rated fill mix, which has more feather content which helps to increase the loft.

To be honest, if i was looking for a more extreme cold weather bag, i probably wouldn't want super high quality down because it's more finicky and collapses easier. While less compressible, and a bit heavier, a higher feather content will help to keep it loftier under adverse and/or longer term conditions.

750 is probably the highest i would go (but no lower than 650). Perhaps overstuffing would compensate some for that?

"But, I would think if two down bags had the same loft, they would probably provide about the same warmth."

Provided they are both baffled… It would be pretty silly to make a non baffled, more extreme cold weather bag, but yah never know. I'm guessing there would be a noticeable difference between a baffled bag and a sewn through, even if they had the same loft.

Problem with a sewn through is it cannot loft like a baffled bag, at least at the stitching, so a sewn through cold weather bag is a non starter.

When trying to reason things like loft and down power I look to those who are making products that are actually working in the field and not just blowing "new & improved advertising smoke" Then I will look to what materials ect. that are work for them.

Being the cheap *ss I am I also have learned to learn from others mistakes. I would much rather take a recommendation from a reputable user than from almost any self promoting manufacturer. BPL members steered me to WM for a colder weather bag and I am a happy camper. Hope you find a good bag for your purposes.

jimmyb

The ratings have changed due to global warming. ;-)

"The ratings have changed due to global warming. ;-)"

No, Andy, it's the guns.

> "The ratings have changed due to global warming. ;-)"
> No, Andy, it's the guns.

At this point the Moderator steps in and bans EVERYONE.

Cheers
PS: humour!

Er…. Roger… is there any way we can 'ban' your humor ? :)

billy