Methods and apparatus for automatically changing between heating and cooling in an HVAC system. In one example, an HVAC controller may monitor the temperature of an inside space of a building, and may switch the HVAC system to cooling when the temperature of the inside space rises above a high switch-point temperature, and may cool the inside space to at least below the high switch-point temperature. The HVAC controller may also switch the HVAC system to heating when the temperature of the inside space falls below a low switch-point temperature and may heat the inside space to at least above the low switch-point temperature. In some cases, after switching to heating or cooling, the HVAC controller may cause the HVAC system to heat or cool the inside space, respectively, to substantially the set-point temperature.