soft, raised surface upon cloth, mid-14c., downy plumage, from Anglo-French pyle or Middle Dutch pijl, both from Latin pilus a hair (source of Italian pelo, Old French pel). Phonological evidence rules out transmission of the English word via Old French cognate peil, poil. Meaning nap upon cloth is from 1560s.
Updated 01/08/17. 1  of 06. Gas Furnace Types and Efficiency Ratings BanksPhotos / Getty Images The gas furnace in your home is a critically important appliance and one you depend on to work reliably, efficiently and quietly. 2  of 06. Low Efficiency Furnace: 55% to 72% AFUE (obsolete technology) Characteristics. 3  of 06.
Do not block or obstruct air. openings on furnace or spaces ar ound furnace. S In a non-direct vent (1-pipe) application, your furnace uses. air from adjacent to the furnace for combustion and vents flue. gas to the outdoors. This type of application will have only one. pipe running from the furnace to the outdoors.