In reply to UKC/UKH Gear:
Hi - this is Carol McDermott and I am the owner of Lightwave (and by default, designer).
I notice a lot of discussions about temperature ratings. On this I have a number points:
1. The purpose of the EN rating is to provide a standardized basis of comparison, and is not the ultimate judgement of how warm a sleeping bag is. In my experience, I feel the EN ratings are quite fairly accurate.
2. There are criticisms of the EN test method. This is irrelevant - there is no perfect test method and each one has strengths and weaknesses. The important thing is to have a standardised basis of comparison.
3. Most brands issue their own assessment of how warm a bag is, mostly to complement an EN rating, but not always. Pre EN-ratings, this was how it was always done. The problem was, and why it lead to the call for a standardised method, that slowly these performance claims did start to creep into the realms of slight exaggeration and, on occasion, straight fiction. Basically, brand X's was always 1 or 2 degrees warmer, etc etc. What do you do when you're trying to sell sleeping bags?
4. The difficulty with "self or brand-assessment" is that what is right for one (usually experienced user or group of users) is not the same for another (and frequently inexperienced user who is dependant upon other's guidelines). The idea of the EN rating is to provide some objectivity, and also, some safety. The ratings are quite conservative. It is better for the customer to be too warm than cold, especially if it is a first purchase.
5. The reality is there is very little difference in the performance of sleeping bags with comparable amount of down fill and nominal difference in fill-power. One or two degrees max, and that is probably due more to how snug the fit/cut is than anything else (because everything else is more or less the same - no one has a monopoly in a "superior" baffle technology or ultra-high grade down).
6. In fact, one of the most useful things any brand can do is actually give the consumer some visibility of what they're buying - for example, just how much down fill is in a bag. It's a bit like saying how many cc your car engine has. Some companies don't state this seemingly straight forward piece of information, so the consumer is left to go by a temperature guide, and if there is no EN rating (complementary or otherwise), then well.....where does one go? I'm not saying brands are intentionally misleading consumers because I feel that this industry has an outstanding level of integrity. However, all brands are under sales pressure, margin pressure and marketing pressure and consequently are terrified of being seen as not being as good as the competition. Truth is - 95% of products are good, if not very good.
As for the Firelight 250 - I can tell you it's marginal at zero, especially when not in a tent. No bag with 250 grams of down at whatever fill-power rating will keep me warm at that temperature. But that's for me. There are also a number of very good competitor products, and that is important for consumers and brands alike. We have no claim to making a product better than anyone else, but this actually applies to all. My philosophy is that, as far as I'm concerned, the paramount factor is that the consumer gets the right product for them (and it most definitely is not always a crux or Lightwave one).
It's ultimately a question of confidence in your brand and product, and how transparent you want to be, or your product to be, in the eyes of your potential customer.