Overview of ..
This part of the Energy Efficiency Manual lowers the
cost of air conditioning by limiting the entry of unwanted solar
heat through the opaque surfaces of the building structure, especially
through roofs and large walls. In buildings such as warehouses,
supermarkets, and department stores, this path for unwanted solar
heat is more important than the cooling load caused by windows.
The heat of sunlight passes through opaque surfaces in a sequence
of steps. First, sunlight is absorbed in the outer skin, raising
its temperature. Then, the absorbed heat is driven through the structure
by the temperature difference between the outer and inner surfaces.
Once inside the envelope, the heat is transferred to the interior
space by radiation, conduction, and convection.
Correspondingly, you can reduce air conditioning energy cost at
each of these stages by using these methods:
- Prevent sunlight from reaching the outside surface by shading.
- Reflect the sunlight from the outside surface.
- Cool the exterior surface.
- Minimize the conduction of heat through the structure by effective
- Vent heat from the inside of the structure, especially from
Here you will learn the details of the techniques that are economical
and reliable. Insulation is the primary method of keeping heat from
passing through the building structure. The appropriate insulation
methods for roofs and walls are explained.
To reflect heat from surfaces, you can apply inexpensive reflective
coatings. This can be tricky, and you will learn to do it correctly.
Effective ventilation of attic spaces is important, but it is rarely
done well. Here you will learn how to ventilate attics to maintain
the lowest possible temperatures, using ventilation fans, roof vents,
turbine ventilators, and other methods.
For exterior shading, you will learn to shade buildings by planting
trees, which is not as simple as it seems. You will learn to select
the best species and locate them properly.