A passive solar design takes full advantage of the sun’s energy by storing the heat during days and using it at nights to make the internal space more comfortable. The construction of passive solar houses requires solar heating and cooling techniques such as natural ventilation, thermal mass, shading, etc.
So, a passive solar building may add to the total cost of construction. A sun-tempered house uses the sun’s heat energy by adding minor changes to the building without increasing the overall cost of construction. Nonetheless, the effective utilization of heat energy in a sun-tempered house is lesser than that of a passive solar house.
What is the Difference Between Passive Solar and Sun-tempered House?
The difference between the passive solar house and the sun-tempered building is summarized in Table-1.
Table-1: Differences between Sun-tempered and Passive Solar Buildings
| Sun-tempered house | Passive solar house |
| Sun-tempering is a term used to describe a house whose incidental solar gain is increased by making minor changes to it. So, it is a sort of halfway building choice instead of the whole-hog choice of true passive solar design. | The passive solar house uses greater heat energy to regulate the internal temperature, and it was originally designed and built to take full advantage of solar energy. |
| The changes involve directing the house’s longwall toward the true south and increasing the surface area of the windows on the south side. This is done by moving windows generally placed on the other side of the house. | Passive solar buildings gain heat energy by orienting the long wall to the true south, so the structure is aligned along an east-west axis. As a result, most of the windows are placed on the south side of the house and limited on the east, west, and north sides. |
| The surface area of the windows need not be greater than that of a conventional building. However, the total surface area of the windows should be around 14% of the total floor area of the house, with 7% on the south side. | Compared to conventional houses, the surface area of windows in passive solar buildings needs to be more. The area of south-facing windows ranges from 12-20% of the total floor area based on the thermal mass in the building. |
| Extra construction cost is not incurred for a new build. Therefore, it rarely costs more than a conventional building. Consequently, it is suitable for homeowners who want energy efficiency but cannot afford a complete passive solar option. | Passive solar buildings involve additional construction costs. So, the initial cost is more than conventional building, but the higher cost is offset by a reduction in energy consumption in the longer run. |
| The existing thermal mass inside the building is not affected, and it typically has adequate storage to prevent overheating and make the building comfortable. | Thermal mass is largely used in passive solar buildings and needs to be positioned carefully to maximize the gain in heat energy. This affects the design and layout of the room, and many passive solar strategies adopt an open plan to enhance heat transfer and airflow. |
| Extra insulation beyond the building code is not required, but it can be provided to further decrease the loss of heat energy inside the house. | It requires complete insulation to properly serve its function. |
| Despite considerably little effort required in the construction stage, the annual heating demand provision of the sun-tempered building is between 20% and 30% based on design, construction, sunlight availability, and local climate. | Annual heating demand provision of passive solar building ranges from 50% to 80% based on design, construction, sunlight availability, and local climate. |
FAQs
Sun-tempering is a term used to describe a house whose incidental solar gain is increased by making minor changes to it. So, it is a sort of halfway building choice instead of the whole-hog choice of true passive solar design.
A passive solar design takes full advantage of the sun’s energy by storing the heat during days and using it at nights to make the internal space more comfortable.
The changes involve directing the house’s longwall toward the true south and increasing the surface area of the windows on the south side. This is done by moving windows generally placed on the other side of the house.
Despite considerably little effort required in the construction stage, the annual heating demand provision of the sun-tempered building is between 20% and 30% based on design, construction, sunlight availability, and local climate.
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