Natural gas gained Friday, but ended lower for the week as traders weighed unusually strong heating demand earlier in the week against forecasts for more moderate temperatures. Natural gas for February delivery settled up 4.8 cents, or 1.2%, to $4.053 a million British thermal units on the New York Mercantile Exchange. Prices fell 5.8% on the week, the worst one-week decline since November. Prices traded above $4.25/mmBtu earlier in the week as record-cold temperatures across the central and eastern U.S. fueled demand for gas-powered heating in homes and offices. About half of U.S. households use natural gas as their primary heating fuel, according to the U.S. Energy Information Administration. U.S. natural-gas demand hit a record high of 138.9 billion cubic feet […]