European Union energy ministers want to crack down on domestic appliances, sometimes called vampires, that suck energy when in “standby,” or off, mode. The ministers want to halve “standby losses” by 2010 and are pushing for voluntary agreements and labeling to do the job, but warned that if these efforts aren’t successful they would consider legislation to set minimum efficiency standards. Electricity wasted by domestic appliances accounts for up to 10 percent of household energy use, officials said, about the same amount of power that is currently generated in Europe from renewable sources such as wind and solar power.