It seems that sleeping bag ratings have no consistency. Temperature ratings are still determined entirely by the manufacturers of the bags. My 3-pound Sierra Designs bag, for example, was rated to 20 degrees. Honestly, it never kept me as warm as my 17-ounce Western Mountaineering sleeping bag, which is only rated down to 40 degrees. Isn’t this a problem when you buy a bag? Maybe a 45-degree bag will keep you warmer than a 30-degree bag.
Consistent Sleeping Bag Ratings
No matter what temperature a bag is rated for, under any system of testing, it won’t necessarily keep you warm to that temperature. We can’t solve the problem of people having different metabolisms and bodies. A particular bag might be good for one person down to 20 degrees, while for another it is only good to 40 degrees. You generally can figure out if you are a cold or a warm sleeper, but that doesn’t help if you don’t know whether a bag is rated too high or too low.
You need to know that if a bag says 30 degrees it will keep you warmer than one that says 40 degrees. With that, even if you add or subtract 10 or 20 degrees for your personal tastes, you can still figure out which bag is the warmer one. How do we get this consistency?
Begin testing with any sleeping bag, by putting a bag of water in it that is human-sized, weighing perhaps 160 pounds. Have three standard sizes for small, regular and large sleeping bags. Always start with the water temperature at 100 degrees Fahrenheit, and measure how long before it drops to 90 degrees. External air temperature has to always be the same too, whther it is 60 degrees or 40.
The numbers are not crucial. What’s important here is that once the standards are chosen, every bag is tested the same way, with the same conditions (even the temperature and material of the testing platform would have to be the same). This is what will give consistency to the sleeping bag ratings for warmth.
Now, if a bag rated to 40 degrees keeps the water above 90 for two hours, a bag rated for 30 would obviously have to keep it above 90 degrees for a longer time. Pegging heat-retention times to specific temperature ratings would be a bit tricky at first. However, once done, each new bag on the market could be submitted to the testing and quickly given a consistent rating. We would know that a lower rating would always mean a warmer bag, degree-by-degree. We could even have old bags tested to see if it is time to replace them.
Would manufacturers pay a private testing company to have their bags rated? Some, at first, because it would be a an advantage for those companies who are already conservative in their temperature ratings. They would have “proof” that the bags are even warmer than they were claiming. Then, eventually, all bag makers would feel some motivation to have their sleeping bags tested, because consumers would be wary about buying ones that weren’t tested.
I hope someone will take this idea and run with it. An existing consumer rating company, like Consumer Reports, could do this on their own and report the results. Even if they listed the bags without temperature ratings, but in absolute order by which held the heat in the best, it would be very useful. One could look at the list and if their current bag kept them warm to 25 degrees, they would know that any bag higher on the list would be warmer. Isn’t it time for consistent sleeping bag ratings?
HDTV Vs. LCD
HDTV – The next generation of TV, or the next 8 track cartridge format. That’s the important question for anyone looking to invest in a new HDTV television. There have been so many different video, tape and sound system formats that the consumer could be forgiven for cynicism and exercising more than a touch of caution.
The HDTV format has been put together by an industry wide group of US researchers and manufacturers, rather than any one manufacturer. It should not be subject to the inter-manufacturer squabbling that killed the 8-track cartridge or Beta format video recording.
HDTV offers a spectacular combination of color intensity and Dolby Digital surround sound that has impressed most reviewers. Giving cinema-like sound and picture quality.
Gas Plasma HDTV screens offer a higher degree of contrast than the competing LCD flat screen TVs. This means the TV has a visible and bright picture, even in a brightly lit room, no more closing the drapes to watch a football game in the afternoon. The Plasma screen also has a much wider viewing angle, so the whole family can watch from around the room. LCD screens have improved in this regard, but are still limited. The colors on an LCD screen change once you are not directly in front or within 10 degrees of a centre line.
If your new television screen is intended for use as a video game screen as well, then the choice is more difficult. This is because gas plasma screens do suffer from “Burn in”. Burn in is where an image that has been displayed for an extended period of time leaves an after-image on the screen even after it is removed. This can be a problem with video gamers because game on-screen control panels tend to be static and would cause “Burn in.”