Andrew, members here typically use the block heater all the way through summer because of the benefits it offers. I'm in MN and I can tell you without a doubt (even though I don't drive an FEH!) that the block heater is worth the investment. Consider that the most wear for your engine occurs when the engine is cold and I think you'll agree that the block heater is worth the enhancement in engine longevity alone -- even ignoring all the other benefits you'll get! Welcome to the forums and do let us know as you come up with more questions -- we love to help!