Solar thermal systems have a lot of cons. Combination with another auxiliary heat resources helps to avoid of solar thermal systems deficient. The general aim of the paper is to explore solar systems combination with different secondary fuels –biomass, natural gas, heat pump and electricity. To achieve the objectives are being carried out in a realistic analysis of the objects in the Latvian territory. Were performed measurements and processed data to determine the suitability of the particular combination of Latvian conditions - advantages and disadvantages. An example an information building of the North Vidzeme Biosphere Reserve is heating with system, which is combined from solar collectors and heat pump (with 11 probes). Is used solar collectors site on the Latvian Academy of Institute of Physical Energy solar energy polygon, which gives very accurate data about solar energy using in Latvia. Are used data from a similar pilot projects. Simulation program for solar combisystems helps to fully capture the data of analysis. Certainly important factors in determining the effectiveness of the combination are their construction and operating costs. Costs are affected by heat availability in Latvia environment. In the paper are given transparent results, various recommendations and few suggestions.