minimize rent loss while renovating a multifamily building

Hi everyone, I just bought a 6 unit multifamily building in Somerville Massachusetts area (close to Harvard University). I am planning to redo all the bathrooms and kitchens for all units. This is an expensive area and the carrying cost is high. I really need as much rental income as possible to offset those costs. What are the best ways to minimize rent loss while accomplish my goal of updating all units by the end of the year? Thanks in advance for your help!  Mindy