The single most widely applicable passive solar design option is thermal or Trombe walls. The option works in every climate and every location, from the hottest and sunniest to the coldest and darkest. But like everything, Trombe walls have their disadvantages as well.
- Trombe walls are the most flexible solar option: they work in mild climates as well as in extreme cold.
- They can even be used to cool a building instead of heating it.
- They stop sun drenching, reducing glare on furnishings compared to direct gain designs.
- They are ideal for home offices, television rooms, and dark bedrooms.
- They work best for nighttime heating, though they are flexible.
- They provide thermal mass in a concentrated area without taking up living space.
- They make for comfortable, quiet rooms with stable temperatures.
- They are attractive when viewed from outside or inside.
- Trombe walls can add to construction costs, partly because of the glazing but mostly because the foundations need to support significant extra weight.
- They can become serious heat sinks, losing a great deal of warmth at night unless they are insulated.
- Covering them every night can be a real hassle, especially with external rigid foam panels (you have to go outside in winter).
- Operating louvers or dampers to close the vents is an additional hassle.
- They reduce daylighting and access to panoramic views.