Refine by


Passive Heating and Cooling

Library Page

Passive Cooling

Just like passive heating, cooling your building using passive strategies is important for reducing energy usage in your building. Specifically, utilizing passive cooling strategies like natural ventilation, air cooling, and shades can reduce your demand for mechanical cooling while maintaining thermal comfort.

Library Page

Passive Heating

Passive heating uses the energy of the sun to keep occupants comfortable without the use of mechanical systems. These concepts will help you design for passive heating.

Library Page

Thermal Mass

Thermal mass is a material's resistance to change in temperature.  Objects with high thermal mass absorb and retain heat.  Thermal mass is crucial to good passive solar heating design, especially in locations that have large swings of temperature from day to night.  

Library Page

Trombe Wall and Attached Sunspace

A Trombe wall is a system for indirect solar heat gain that is a good example of thermal mass, solar gain, and glazing properties used together to achieve human comfort goals passively.  It consists of a dark colored wall of high thermal mass facing the sun, with glazing spaced in front to leave a small air space.

Library Page

Stack Ventilation and Bernoulli's Principle

Stack ventilation and Bernoulli's principle are two kinds of passive ventilation that use air pressure differences due to height to pull air through the building.  Lower pressures higher in the building help pull air upward.

Library Page

Night-Purge Ventilation

Night-Purge Ventilation (or "night flushing") keeps windows closed during the day, but open at night to flush warm air out of the building and cool thermal mass for the next day. Night flushing is only suitable for climates with a relatively high temperature range from day to night, like the desert.

Library Page

Natural Ventilation

Natural ventilation, also called passive ventilation, uses natural outside air movement and pressure differences to both passively cool and ventilate a building. It can include design strategies like wind ventilation, the stack effect, and night purge ventilation.

Library Page

Massing & Orientation for Heating

Massing and orientation are important design factors to consider for passive heating. Consider these factors early in the design so that the surface areas exposed to sun at different times of day, building dimensions, and building orientation can all be optimized for passive comfort.  

Library Page

Direct Solar Gain

Direct gain is the heat from the sun being collected and contained in an occupied space. Direct solar gain is important for any site that needs heating, because it is the simplest and least costly way of passively heating a building with the sun.  Avoiding direct solar gain is also important in hot sunny climates.

Library Page

Shading for Solar Heat Gain

Shades can keep the heat and glare of direct sun from coming through windows. They can also keep direct sunlight off of walls or roofs, to reduce cooling loads.