Solar hot air systems heat air in a flat plate collector. Hot air flat plate collectors work just like your closed car in the sunlight. You know how hot a closed car can get! Well that is pretty much how a hot air collector works. Fans circulate air through ducts into the solar air collector where the air is warmed and then circulated via ducts back into the home’s interior spaces.
Usually the air-based solar heating system uses the home’s existing heating system ducting so that the existing heating system can act as a back-up for times when sunlight is scarce. Also if the existing whole house ducting is used all rooms can receive the heat from the solar collectors.
Air-base solar heating systems can also be installed in room windows where heat may be needed without connecting to the home heating system. Air collectors can be installed on exterior walls for heating one or more rooms. Although factory-built collectors for on-site installation are available, do-it-yourselfers may choose to build and install their own collector.
Simple "window box collectors" fit in an existing window opening. They can be active (using a fan) or passive. In passive types, air enters the bottom of the collector, rises as it is heated, and enters the room. In active types, air is drawn into the collector with a small fan, is heated by the collector and then blown into the room. These systems only provide a small amount of heat, since the collector area is relatively small but could be just the amount of heat needed to take the chill off a room. Also multiple hot air collectors can be used to provide more heat if needed.
Air-base solar heating systems can also be installed in room windows where heat may be needed without connecting to the home heating system. Air collectors can be installed on exterior walls for heating one or more rooms. Although factory-built collectors for on-site installation are available, do-it-yourselfers may choose to build and install their own collector.
