The fast growing of energy in the world has become a high concern over some source problems 
in energy calculations of economy, where the buildings now described as one of the main energy 
consumers  for  about  33.35%  worldwide.  This  paper  aims  to  review  and  investigate  on  the 
Swedish  conventional  buildings  for  a  quantitative  research.  To  analyze  the  case  study,  latest 
energy  analysis  software  (LEAP)  used  as  an  environmental  simulation  and  assessment  tool  for 
the calculations. The first step is to lead toward studying the EU buildings in general with a case 
study  focusing  on  Swedish  conventional  buildings  for  the  design  and  method  of  calculation  in 
energy  performance  and  consumption.  In  the  second  step,  analyzing  the  data  for  the  energy 
consumption  and  comprehensive  model  for  a  conventional  building  (M-building)  in 
Stockholm/Sweden.  In  the  last  step,  a  broad  energy  consumption  that  has  been  performed  with 
the foundation of model for the evaluation of the power used as a part of the Swedish structures. 
Under the IPCC fifth assessments, the result shows that conventional buildings will expend more 
energy than other new sustainable buildings in Sweden for about 70% more. However, about 60 
kWh  of  energy  will  be  used  for  saving,  which  is  approximately  2%  for  the  management, 
transportations and other sectors/segments with a total of 263 kWh/   as energy consumption.