This work presents methodology and the Case study about energy savings and improvement of indoor comfort at hospitals. There are two major aspects for energy saving in the health care sector. First is the potential for the savings via the combination of engineering tools: Improving the building’s insulation and ventilation systems; recovery of heat from ventilation systems and warm waste water; improvement of electrical systems; changes in user behaviours. The other is improvement of indoor comfort in the buildings with a high level of hygiene requirements. Case analysis has been performed as analysis of the status quo of energy and indoor comfort, via full energy assessment method; and the development of two improvement scenarios – one that is moderate and related to short term investments; and other is a sample scenario for major refurbishment involving long term investments. The use of the use of indoor climate and energy simulation tools is an important part of the Case study. This work should be useful to professionals in hospital maintenance and engineering, especially when facing refurbishment or need to cut the energy costs.