Heating for comfort in buildings can be harnessed from solar energy through systems that can be thought of as enlarged versions of water heating systems. The most common heat transfer fluids in these systems are water and air. This report focusses on such system, which comprise collectors, a storage unit, the load (i.e., the house or building to be heated), and control mechanisms. In temperate climates, achieving an optimal balance between solar energy and supplementary (i.e., conventional), energy sources poses a significant challenge. This report addresses the problem of determining the most efficient combination of these energy sources. “Solar houses” are buildings designed with large windows facing the equator (south in the northern hemisphere or north in the southern hemisphere), allowing them to capture solar radiation when the sun is low in the winter sky. While the benefits of well-placed windows are significant, in colder climates, it's essential to manage losses during periods of low radiation, nighttime, and cloudy weather to ensure a net gain in heat. Additionally, this examination includes a description of a solar and pellet combi-system implemented for a demonstration pilot project. The report also identify the main parameters of this system and analyze its performance data for the first month of operation. Furthermore, it will be presented a financial analysis based on simulated data and actual system performance to evaluate various heat supply scenarios.