· Addition to exterior of house or somewhat nestled inside some area of the house
· Can be at ground level or below ground level (pit sunspace- below frost line). Good because relatively constant temps due to the surrounding earth.

Heating

Sunlight enters the sunspace through a south-facing façade of glass or plastic and is this incoming radiation takes the form of heat. Sunspaces are just a means of collecting the heat. Different means of storing and distributing the heat include:

· Open wall
There is no separation between the sunspace and the living space within the house. The warmed air is allowed to move freely to heat the living and the sun space. Some of the heat can also be absorbed and stored in the floor slab (usually concrete) or other storage components within both spaces. However, the main disadvantage is that the temp of the sunspace must be maintained at the same level as that of the other spaces. This means that at night and during cloudy days, heat will be escaping from the sunspace and additional active heating systems will be needed. Also shading becomes important to reduce glare as direct sunlight enters the room. To prevent this loss of heat, high performance glazing should be used for the sunspace. In mild to moderate climates, double pane low-e glass should be used. In colder climates, low-e glass with a possible gas layer between the panes (argon or krypton). In more extreme climates or for greater efficiency, glazing with suspended films or movable insulation may be used.

· Direct gain
Similar to the open wall system, but with a shared wall separating the sunspace from the living space. This is beneficial because it eliminates the need to actively heat the sunspace at night and during cloudy days. These shared walls are typically double glazed glass or plastic panels that can open to facilitate the sharing of heat between the sunspace and the living spaces. When these panels are closed, the sunspace acts more as a thermal buffer for reducing the temperature difference between outside and in. It is also possible to utilize heavy drapes to cover the glass shared wall at night, or more effectively to place movable insulation on the façade of the sunspace itself to prevent the loss of heat.

· Convective air flow
Similar to the direct gain system, except that in this scheme the shared wall has vents at both the top and the bottom to allow for air to circulate through the sunspace picking up heat and moving into the living space to release the heat. This air circulation is completely passive and relies on the different densities of warm and cool air to cause this convection. The air warmed in the sunspace rises and flows out through the upper vent which causes cooler air from the living space to flow into the sunspace through the lower vents. The incoming radiation heats this air and the cycle continues. At night or during cloudy days when you want to prevent the warmer indoor air from escaping, both upper and lower vents would be closed manually or automatically.

· Thermal storage walls
The shared wall between the sunspace and the living space is a thermal mass. The wall absorbs incoming solar radiation and stores it during the day. Then at night,it reradiates the heat it has stored to the living space as well as the sunspace. The efficiency of this system is greatly improved with the use of glazing or movable insulation on the exterior façade of the sunspace. It is also possible to combine the convective scheme with the use of a thermal wall to combine heating with ventilation.

 

Cooling

During the summer, sunspaces tend to overheat and are occasionally the source of unwanted heat gain to the house. To prevent this, shading devices such as louvers, overhangs, trees, and movable insulation can be used to prevent solar radiation from penetrating into the sunspace. To further cool the sunspace, it would be possible to open upper and lower vents in the façade of the sunspace to encourage airflow through the space.