The state of Lower Saxony decided to smoke detectors in March 2012, affecting all private apartments in the region. For existing buildings, there is a fixed transitional period, new and renovations are to be equipped with smoke detectors from completion. Read the details of the law here. Fr What deadlines apply to the smoke detector requirement in Lower Saxony? Am Use the best quality lithium batteries for your smoke detectors, which can last for the full life of 10 years. Cheap batteries usually last a maximum of one year, causing work and consequential costs.