S

Saturation
The maximum mass of vapour that can be contained by air at any given temperature; the point at which relative humidity reaches 100%.

Setpoint temperature (°C)
The setting on a thermostat controlling the output of a heating appliance in a room or building.

Shading
The most efficient way of protecting a building is to shade its windows and other apertures from unwanted direct sunlight. The degree and type of shade necessary depends on the position of the sun and the position and geometry of the part of the building being shaded.

In summer, when the solar beam falls on the south side of a building the sun is fairly high in the sky. Thus any south facing apertures receive less solar radiation and it is easy to protect them. Shading of east and west facing windows, on the other hand, poses a greater problem because the sun is low in the sky when it is in the east or west and a greater amount of solar radiation reaches these windows. One solution, therefore, is to consider reducing as far as possible the area of east and west-facing glazing.

Skylight
Skylight is sunlight scattered in the earth's atmosphere. Direct - not scattered - light reaching the surface of the earth is disregarded.

Solar chimney
A solar chimney creates a rising hot air current. A tower in the form of a vertical Venturi with a convergent-divergent section uses the temperature gradient to increase the air speed. The solar chimney principle can be used in buildings to give a boost to natural ventilation.

Solar heat gain coefficient (SHGC, g-value)
Solar Heat Gain Coefficient (SHGC) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed, then subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window's SHGC, the less solar heat it transmits.

Solar transmission (or solar transmittance)
The ratio of global solar radiation transmitted by a glazing material to the radiation incident on the outside surface of the material.

Specific heat capacity (Wh/(kg K) or J/(kg K))
The amount of heat required to raise the temperature of a unit mass of a material by one degree.

Stack effect
The tendency of air to rise when heated.

Standardized eye
The standardized eye defines the luminous sensitivity of the human eye for different colors. A blue light source must emit significantly more radiation than a green one to achieve the subjective sensation of equal luminosity.

Storage materials
The ability of a material to store heat is usually expressed in terms of its specific heat capacity - the heat stored in a unit volume of material per degree of temperature rise. Materials with a good thermal conductivity accumulate heat relatively quickly. Dense materials such as natural stone, concrete and brick are traditionally chosen for the parts of a building where good heat storage is required. The storage capacity of masonry ranges from 0.204 kWh/m³ for cellular concrete to 0.784 kWh/m³ for heavyweight concrete.

In a lightweight building or for parts of any building where increased storage is required without the use of massive materials, substances with a higher storage capacity can be used. Examples are water (which has a storage capacity of 1.157 kWh/m³ at 20 °C), other liquids, and materials which change phase.

(Inside / outside) Surface conductance (W / (m² W))
See Heat transfer coefficient.

Surface resistance (m²K/W)
The thermal resistance at the surface of a material; this consists of a convective component which depends on the rate of air flow over the surface, and a radiative component which depends on the temperature and emissivity of the surface.