Yesterday I read some BPL posts answering questions about low budget garment outfitting for ultralight backpacking. It struck me how confusing all the options must be for a newbie. I then thought that warmth relative to Polartec fleece products might be the easiest way for people to understand their options without having to wade through technical jargon or vague environmental descriptions. This post is an attempt to see if this different approach makes sense to people.
If I say, “It is the same warmth as a Polartec 300”, everyone can understand.
If I say, “The Patagonia Polarguard Delta Pullover’s intrinsic clo value is 1.06 and its total clo value is .509, the experts understand, but the laymen are confused.
If I say, “The Patagonia Polarguard Delta Pullover kept me warm at 30F around camp, the laymen think they understand but the experts know that the information is of little practical value to either the laymen or the expert. Without knowing the wind rate, the reporting persons BMR, the MET rates and durations for their camp activities, and the change in the reporting persons core temperature at the beginning and the end of the camp activities it is impossible to ascertain the insulation value of the garment they are reviewing.
I created the following chart to be Montbell centric. The other garments I listed are common alternatives to comparable Montbell garments.
Trying to determine the warmth of a garment by just measuring its loft is a measure of futility. For example, the Patagonia Polarguard Delta Pullover and a Wild Things Primaloft One sweater both have a loft of .6”. The Wild Things sweater is more than 27% warmer. The Montbell Alpine jacket has 2” of loft and box baffles yet the New Balance Fugu, which uses sewn through construction, and only has 1.5” loft is 64% warmer. The Montbell Alpine Jacket and the Montbell Permafrost Parka both use box baffles and have 2” of loft; the Permafrost Parka is 41% warmer. A Polartec 300 jacket has .25”loft and a Patagonia Polarguard Delta pullover has .6” loft and yet their insulation value is the same. The only two cases in which the loft is relevant is if you want to compare synthetic garments using the same insulation type and quilting. The other case is base layer garments; their warmth is correlated with their thickness.
In January 2010 there were a number of posts asking for clarification of the specific fabrics I tested. I answered these questions in separate forum posts. In addition, I updated my chart to includes fabric weight information. Version 2 of the chart is as follows:
In January 2011 there was a request to add information regarding how wind would affect the insulation value of each garment. I answered this related question is new post at http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=42263&skip_to_post=359270#359270