The building sector is one of the most dynamically evolving field with an expectation to provide comfortable, clean and healthy indoor environment with less energy consumption. This acceptable indoor condition is created with a combination of heating/cooling systems and ventilation strategies. There are various systems available, which can deliver heating/cooling as well as ventilation to a dwelling space. These systems involve different heat transfer mechanisms and ventilation strategies: as a result, their performance would be different. Accordingly, the performance of these systems would affect indoor conditions. The process of providing an acceptable indoor environment with minimized energy use can be challenging. In addition to that, there is also a keen interest to reduce the current trend of the building energy consumption as low as possible without affecting the required, comfortable indoor environment. Therefore, the requirement of comprehensive field research that studies and compares most of currently available space heating systems, as well as ventilation strategies, is highly vital to provide information about their actual and relative performance in a real scenario. This research project conducts a field experiment that studies, heating systems, ventilation strategies, and ventilation flow rates. The first part is done by running two different heating systems at a time out of four heating systems (electrical baseboard heater, portable radiator heater, heat pump, and Radiant floor heating systems) in identical full-scale test building with similar ventilation strategy and similar ventilation flow rate. Whereas, the second group of experiments compare two ventilation strategies (mixed ventilation and underfloor ventilation) inside two test buildings with similar heating systems and ventilation flow rate. The third group of comparison compares three ventilation flow rates (15 cfm, 7.5 cfm, and 5 cfm) in the test buildings with similar heating systems and ventilation strategies. Various indicators and indoor environmental elements are used to conduct the comparisons. In the first case where heating systems are compared, the thermal energy provide by the systems are used for comparison. In addition, the thermal comfort, local thermal discomfort, temperature distribution and RH distribution are used to assess and compare the indoor environment produced by the systems. Whereas, the ventilation strategies are compared using indoor environmental element (temperature, relative humidity, CO2, and air velocity) distributions. Finally, the comparison of ventilation flow rates is performed using contaminant removal effectiveness, indoor air quality number, and indoor environmental element distributions. The findings from the experiments indicate that all of the heating systems provide similar daily thermal energy between 10 kWh and 14 kWh based on the outdoor weather condition. In addition, all of the heating systems produce a thermally comfortable indoor environment for standing person. Whereas, the ventilation strategies comparison shows that mixed ventilation strategy performance is slightly better than an underfloor Ventilation strategy by creating marginally uniform CO2 and RH distribution. Moreover, the results of the ventilation flow rates comparison show that the temperature and air velocity distribution find similar while using all the three ventilation flow rates. But the higher ventilation flow rate removes relatively more RH and CO2 in comparison to the lower one. Accordingly, the higher ventilation flow rates depict higher contaminant removal rate and high indoor air quality number relative to lower ventilation flow rate.