I have a need to put up a bright out door light. I'm looking at the High Pressure Sodium or Mercury Vapor lights. Looks like HPS lights are more energy efficient, but slight drops in voltage like when someone flips on another appliance like washing machine, dishwasher or well pump are said to cause the light to switch off. True or not? Mercury Vapor lights seem like energy hogs, but are nice and bright/white. The goal here is to illuminate one side of the house that is completely dark right now...Garbage can, basket ball hoop and nosey neighbors over there (she likes to turn off all her lights and hang out on her deck and watch us to see what we're up to and I want to illuminate the hell out of the property over there including her) What is best, most energy efficient option?