A secondary source of heat may be required depending on personal preferences and location. The swimming pool is required to be heated with its own heater, and, when not in use, covered with the solar cover. To heat the space, you will have a combination of the radiant heat from the pool, the greenhouse effect from the polycarbonate sheet, and the heat from the secondary source will provide more than enough heat creating a pleasant environment for swimming. Ideal temperature inside the space during non-summer days is 74 degrees for most people. If it is warmer than 74 degrees, then opening windows and using exhaust fans help to control the climate and environment inside the space.