How do you choose the best orientation for passive solar heating and cooling?

1 The importance of orientation

Orientation is the direction that your building faces in relation to the sun, the wind, and the landscape. It affects how much solar heat and light you can capture, store, and distribute throughout your space. It also influences how well you can ventilate, shade, and insulate your building to prevent overheating or heat loss. Ideally, you want to orient your building to maximize solar gain in winter and minimize it in summer, while also considering the prevailing winds and the site features.

2 The optimal angle for solar exposure

The optimal angle for solar exposure depends on your latitude, the season, and the time of day. Generally, the sun is lower in the sky in winter and higher in summer, and it moves from east to west during the day. This means that the south-facing side of your building (in the northern hemisphere) or the north-facing side (in the southern hemisphere) will receive the most direct sunlight throughout the year. Therefore, you should place your main living areas, windows, and thermal mass elements on this side to capture and store the solar heat. You should also use adjustable shading devices, such as awnings, blinds, or shutters, to control the amount of sunlight entering your space.

3 The role of wind and landscape

Wind and landscape can also affect your passive solar design by providing natural cooling, ventilation, and protection. You should orient your building to take advantage of the prevailing breezes in summer and block them in winter. You can use windows, doors, vents, or fans to create cross-ventilation and remove excess heat and humidity from your space. You can also use trees, shrubs, fences, or hills to shade, shelter, or channel the wind around your building. However, you should avoid placing any obstacles that could block the sun from reaching your south- or north-facing side.

4 The shape and size of your building

The shape and size of your building can also influence your passive solar performance by affecting the surface area, volume, and aspect ratio of your space. Generally, you want to minimize the surface area exposed to the cold or hot air and maximize the volume enclosed by the building envelope. This will reduce the heat transfer and improve the insulation of your space. You also want to have a long and narrow shape that extends along the east-west axis and has a high aspect ratio (the ratio of length to width). This will increase the solar exposure of your south- or north-facing side and decrease it on the east and west sides.

5 The layout and zoning of your space

The layout and zoning of your space can also help you optimize your passive solar design by creating different thermal zones within your building. You should group together the rooms that have similar heating and cooling needs and separate them from the ones that have different needs. For example, you can place your living room, kitchen, and dining room on the south- or north-facing side, where they can benefit from the solar heat and light. You can place your bedrooms, bathrooms, and closets on the east or west side, where they can be cooler and darker. You can also use buffer zones, such as hallways, staircases, or garages, to create a thermal barrier between the different zones.

6 The integration of passive solar elements

The integration of passive solar elements is the final step to choose the best orientation for passive solar heating and cooling. You should select and combine the appropriate elements for your climate, site, and building type. These elements include windows, skylights, doors, walls, floors, roofs, shading devices, thermal mass, insulation, ventilation, and landscaping. You should design them to work together as a system that collects, stores, distributes, and regulates the solar heat and light in your space. You should also consider their aesthetic, functional, and structural aspects.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?