One of the most pressing problems in the Latvian economy is related to the energy sector. The most characteristic feature is coupled with the low efficiency of thermal energy consumption of households as a result of poor insulation of existing buildings in Latvia. Solving energy sector problems requires a comprehensive decision, both in energy production and consumption. It is therefore necessary to develop energy sector model to be able to evaluate not only the energy consumption growth and the factors affecting it directly, but also the feedback caused by the increase of the efficiency growth. The model shown in the article has been developed using system dynamic method. Latvian energy sector model consists of resources, production and consumption blocks. A separate place is taken by electricity generation hydroelectric power plants (HPP), net imports of electricity and so on. Resource blocks consist of primary energy resource blocks: petroleum products, solid fuel, wood and gas blocks. Primary energy resources are used for production of other energy forms, i.e. heat or electricity production, they are shown in the production blocks. Both the primary energy and produced energy (and electricity generated by HPP) are passed on to final consumers, who make consumer unit blocks. It consists of: transport, agriculture, households and other (industrial and services sectors) blocks. The model key role is to forecast energy consumption by separate groups, both consumers and energy resources groups; to estimate energy sector impact on environment. The model has been developed to estimate the impact of buildings thermo insulation program on Latvian economy.