Passive Solar Design

What is Passive Solar Design?

Passive Solar Design is a simple and common-sense approach to energy efficiency. When done correctly it can be a highly cost-effective way of keeping buildings warm in winter and cool in summer.

It requires a basic understanding of how the sun moves through the sky at different times of the day and year. And it requires a holistic approach to design. The 10 simple steps outlined in this class ALL need to be considered and applied correctly for a passive solar design to work properly. If even one of the steps is done incorrectly serious problems can arise and the resulting building can be hard to heat in the winter and/or hard to keep cool in the summer.

Passive Solar Design is the art of designing energy efficient buildings that make the best use of natural systems for maintaining a comfortable indoor climate. A Passive Solar building uses low winter sun to help keep it warm in winter, and carefully placed shading and natural ventilation to help keep it cool in the summer.

The drawing on the left shows how the low winter sun enters a Passive Solar Home to help to keep it warm.

In summer the roof overhang keeps the sun out to help keep it shady and cool inside.

This is the basic principle of Passive Solar Design but it only works if a number of things are done right. The building has to be oriented the right way, have the right kind of windows in the right locations, the right amount of roof overhang, correctly sized and placed thermal mass, and very good insulation and air sealing.

What does a Passive Solar Home look like?

The photo on the left shows a Passive Solar, Straw-bale Home that one of our expert consultants designed and built. But you wouldn’t know it if you were driving by because it looks like every other house on the street. The owners know the difference though, every month when they get their utility bill and see how little energy they have used.

Every well-designed Passive Solar building is different because every site is different in terms of its macro, and micro-climate, access to sun and breezes, views, landscape, etc, etc. Passive Solar Design requires a holistic approach that considers many different factors simultaneously in the decision making process.

These factors can be divided into ten fundamental principles which can be summarized as follows:

10 Principles of Passive Solar Design

1. Site Selection – choose a site with good solar access but protected from hot afternoon sun, open to cooling breezes but sheltered from cold winter winds, and preferably close to existing services to limit urban sprawl and the amount of driving required.
2. Orientation – orient the building with the long axis facing solar south to maximize solar gain in the winter and limit western exposure in the summer.
3. Window Placement – select high-performance windows and place them carefully to maximize winter heat gain and minimize summer heat gain.
4. Shading – carefully configure the eave overhangs and other shading devices to allow low winter sun into the building and keep high summer sun out.
5. Room Layout – locate the rooms that will be used most during the day on the south side for natural light. Keep all plumbing locations as close as possible to the water heater to reduce wasted water and energy.
6. Insulation – provide a continuous insulation layer, with appropriate thicknesses for the climate, around the entire conditioned space of the building to minimize heat loss in winter and heat gain in summer.
7. Air-sealing – there should also be a continuous air-barrier layer around the entire envelope in contact with the insulation layer to minimize heat loss in winter and heat gain in summer.
8. Ventilation – every building requires ventilation to maintain good indoor air quality. In energy efficient and air-tight ones this requires the use of a heat (or energy) recovery ventilation system.
9. Thermal Mass – use heavy materials like concrete, brick, stone, and tile in appropriate areas and thicknesses on the inside of the insulated envelope to store heat and help even out temperature fluctuations.
10. Landscaping – carefully thought-out landscaping and planting can help to maximize the performance of a Passive Solar Design and can help solve all sorts of problems with imperfect situations.

Who can design a Passive Solar House?

While each of the steps in Passive Solar Design is fairly simple and common sense, they ALL need to be done right and to function together in order for the whole building to work properly. Whether you’re a homeowner, a builder, or an architect we can help guide your project to a successful conclusion. We also offer consultation and training for individuals and groups on the Fundamentals of Passive Solar Design.

Expert Passive Solar Design Consultants

At Energetechs, we have expert Passive Solar Design consultants available by phone or email to help answer your questions. We also offer a one-hour FREE design consultation on any new project. So you have nothing to lose and a great deal to gain from giving us call.

CLICK HERE to view one of our presentations that outlines Passive Solar Design in10 simple steps.

CONTACT US – Energetechs, Inc., – ph.