Thermal I — Passive Solar & Comfort
Calculate the sun's position for any date at your site, establish true south in the field, size an overhang that shades fully in summer and admits fully in winter, and size glazing against the mass available to absorb it.
What you'll be able to do
- Calculate solar altitude and azimuth for any date and latitude
- Establish true south on site and correct for magnetic declination
- Size a south overhang from the geometry rather than a rule of thumb
- Match glazing area to available thermal mass
Syllabus
6 parts · 19 lessons · 145 quiz questions · ≈5.7 hours of reading · sign in to open lessons
Part A COMFORT
- 1 What Thermal Comfort Actually Is 16 min · 6 q
- 2 Adaptive Comfort and Occupant Control 15 min · 7 q
- 3 Reading a Climate 17 min · 7 q
Part B SOLAR GEOMETRY
- 4 The Sun's Path 17 min · 7 q
- 5 Finding True South 25 min · 9 q
- 6 Overhang Design 19 min · 8 q
Part C THE THREE PASSIVE SOLAR SYSTEMS
- 7 Heat Flow 13 min · 6 q
- 8 Radiant Energy and the Greenhouse Effect 12 min · 6 q
- 9 Direct Gain 16 min · 7 q
- 10 Indirect Gain — Trombe Walls and Thermosiphon 14 min · 6 q
- 11 Isolated Gain — Sunspaces and Greenhouses 16 min · 7 q
Part D TUNING THE SYSTEM
- 12 Glass-to-Mass Ratio and Sizing 27 min · 11 q
- 13 Surface Colour and Absorptance 15 min · 8 q
- 14 Glazing Selection 16 min · 8 q
- 15 Shading Beyond the Overhang 17 min · 8 q
Part E PASSIVE BUILDING AS A STANDARD
- 16 The Five Principles of Passive Building 17 min · 8 q
- 17 Passive House — the Standard 16 min · 8 q
- 18 Resilience 16 min · 8 q
Part F INTEGRATION
- 19 A Worked Design — Taos 25 min · 10 q
Ref Appendices
- A1 Solar Geometry Reference
- A2 Rules of Thumb
- A3 Comfort and Climate Reference
- A4 Passive Solar Design Checklist
Prerequisites
Recommended: Course 1 (Site, Climate & Land Assessment). Pairs with Course 6 (Thermal II).
About this course
Course competency
On completing this course you can calculate the sun's position at your site for any date, establish true south in the field, size a south-facing overhang so it shades fully in summer and admits fully in winter, choose between direct, indirect and isolated gain systems, size glazing against available thermal mass, specify glazing and shading, and explain to a client why the building will be comfortable without a furnace.
Why this course exists
Course 3 and Course 4 built walls. This course decides where the building faces and what the sun does to it — and that decision outranks every material choice that follows.
A superbly built tire wall in a badly oriented building performs worse than an ordinary wall in a well-oriented one. Orientation, glazing area and overhang depth cost nothing at design stage and cannot be changed afterwards. They are the highest-leverage, most irreversible decisions on the project.
Doug Balcomb's line, which every passive solar designer eventually repeats: "Orientation is 80 percent of passive solar design."
What "passive" means, precisely
A passive solar building uses the building itself — its orientation, massing, glazing and materials — as an integrated solar energy system.
No pumps. No controls. No moving parts. No external energy input. Everything responds to an input of energy through the physics of the building.
This is not a poorer version of a mechanical system. It is a different category of thing, and it has a property no mechanical system has: it cannot break down, because there is nothing in it to break.
That is the resilience argument, and it is the one that lands hardest with clients. In an extended winter power failure, the interior of a passive solar building will be dramatically warmer than a conventional building — not because a backup ran, but because the building is doing what it always does. For off-grid work, for disaster relief, and for affordable housing where a utility shutoff is a real risk, that property is the whole point.
The numbers that justify the discipline
Buildings account for roughly 30% of global final energy consumption and more than 55% of global electricity consumption. Operationally they produce about 28% of energy-related CO₂ emissions; including the emissions embodied in construction, the figure is just under 40%.
A correction worth carrying forward. Some older Pangea material states that "buildings use about 48% of all electrical energy generated by humanity, of which 40% is for operating and 10% for construction." That is a garbled version of a US-specific figure and it is not correct as stated. Use the IEA figures above. They are more conservative, more defensible, and still make the case overwhelmingly — buildings are the largest single lever available.
And buildings do not have to use fossil fuels at all. Zero-energy buildings can be built today, and the small residual energy demand can be met from photovoltaic, wind or other renewable sources (Course 10).
Course structure
| Part | Lessons | Subject |
|---|---|---|
| A | 1–3 | Comfort: what it is, how people adapt, and how to read a climate |
| B | 4–6 | Solar geometry: the sun's path, true south, and overhang design |
| C | 7–11 | The three passive solar systems |
| D | 12–15 | Tuning: glass-to-mass ratio, colour, glazing, shading |
| E | 16–18 | Passive building as a standard, and resilience |
| F | 19 | An integrated worked example |
| — | A1–A4 | Appendices: solar reference, rules of thumb, climate data, design checklist |
The public page for this course has the same syllabus without your progress on it - that is the one to send to somebody else.