One of the aspects of passive solar house design that surprised many people is the need for shade. If your heating depends on sunlight, why would you block it? Because not all sunlight is beneficial to a passive solar home – the high summer sun, in particular, can produce far too much heat, requiring some kind of shade to stop your home turning into an oven.
Direct gain passive solar homes have many advantages and disadvantages compared to other approaches. Historically, the first direct gain homes were often a complete mess, because the designers had little understanding of the need to balance things like solar glazing and thermal mass. Modern designs are much better, especially since analysis software is now available to help make the tough decisions.
Thankfully, the days of cookie-cutter houses built quickly to exactly the same design are on their way out. Even in places where the homes are all based on the same floor plan, individual home owners add and change things to suit themselves. One of the easiest things to change in any home is the color of the exterior walls.
In most cases, we talk about thermal mass as something that absorbs and stores useful heat from the sun's light, releasing it when your home gets colder to maintain a comfortable indoor temperature. However, it is possible to use thermal mass as an effective cooling mechanism.
Thermal walls, or Trombe walls, are the single most flexible passive solar option: they work in any climate and on any home, providing extra heat throughout the night after gathering heat during the day.
There are two types of cooling for passive solar homes: stuff that cools the house and stuff that cools the people inside the house. Humans do not react to heat in the same way as building materials, after all! There are two main ways of cooling a home's inhabitants:
As with all passive solar design options, Trombe walls are a great addition to your home design: they retain a lot of heat, helping to reduce your nighttime heating costs throughout the cool period of the year. However, again like all other options, they need to be used correctly or they won't do you any good.
There are two main effects of indoor air pollution. The first is the effect on the home itself: everything gets dirty, especially if the pollution is particulate matter (e.g. soot), and structural problems can arise from things like mold and mildew. The second is the effect on your health if you live in the home. Let's look at what can happen.
Although thermal Trombe walls work well in all climates and for almost any home, you need to choose the correct design for your particular needs. This choice depends on your local climate. Here are some essential guidelines:
