They do help however...they only keep the coolant warm and that means just the top-end of the engine. The real issues in cold weather come from lack..or delay..of lubrication so keeping the lower block and oil from reaching those sub-zero temps might be a better goal..plus as heat rises the top-end still gets some relief. People do it with different types of devices including oil plug and dip-stick heaters, simple automotive heating pad placed under the engine (which works very well), and just placing a simple trouble light with a 40 watt bulb under the engine. And for you a good 0w40 oil will be practically mandatory as well as keeping the battery on a maintainer at all times.