Envelopes for Climate Types
A well-designed envelope responds to the local climate. As described in the Climate page, there are many classifications of climate around the globe, but the summary below shows four common extremes that people design for. Milder climates can use milder versions of these strategies, or mix and match.
Arid Climate Envelope
Tropical Climate Envelope
Cold Climate Envelope
Mixed Cold / Hot Climate Envelope
Envelope Energy Flows
From an energy flow perspective, the envelope is a composition of layers with varying thermal and permeability properties. The envelope may be composed of membranes, sheets, blocks and preassembled components. The choice of envelope is governed by the climate, culture, and available materials. The range of choices in envelope design can be illustrated by two opposite design concepts: the open frame and the closed shell.
In harsh climates, the designer frequently conceives the building envelope as a closed shell and proceeds to selectively punch holes in it to make limited and special contact with the outdoors. This may also be true where there are unwanted external influences such as noise or visual clutter.
When external conditions are very close to the desired internal ones, the envelope often begins as an open structural frame, with pieces of the building skin selectively added to modify only a few outdoor forces.
The flow of heat through a building envelope varies both by season (heat always flows from hot to cold and generally flows from a building in winter and to a building in summer) and by the path of the heat (through the materials of a building’s skin, or by outdoor air entering). These complexities must be considered by a designer who intends to deliver comfort and energy efficiency.
The following links provide more detailed information on building envelope components and the minimum thermal requirements of envelopes for different climates as defined by ASHRAE.