A study of flat-type solar space heating for a residential building has been done. The study includes comparing of several solar radiation estimating methods. Computer simulation is written in Matlab. Full code is listed in the Appendix. The results show that flat-type solar collectors can perform well under the severe weather conditions and the radiation levels of Astana, Kazakhstan. However, the simulation of a solar space heating system compared to an electric resistance heating system showed that the solar heating system that is simulated cannot provide enough heating capacity to heat the building without 50% backup system. In addition, the cost analysis showed that the present worth of the solar heating system can be greater than the electric heating system if the price of solar collectors is less than their current value.