Climate is the most important environmental factor and the first one that architects and engineers should consider when designing a building. To achieve a net zero energy building, the design must consider the building’s specific site climate. The climate can dictate what passive design strategies are most suitable and effective for the building site. For example, strategies that are perfect for a hot dry location may be counterproductive in a cold humid climate.
A site’s climate is dictated by its latitude, altitude, and terrain. A site located at 60°N on a mountain top will require very different design strategies from a site at 7°S at sea level. Climate influences many aspects of building design such as what the indoor temperature should be, what are the factors defining human thermal comfort, and predicting energy loads for the building.
A common misconception is that climate and weather are interchangeable terms to describe the same thing. This is not true. Climate refers to the average atmospheric conditions over a long period of time where weather refers to the daily temperatures and atmospheric conditions. For example, climate change refers to the changing daily weather patterns over a long period of time.
Designers can choose passive design strategies suited for their building based on the climate type. Specific classifications of climates vary, however they can all be useful in determining appropriate design strategies. For instance, the Köppen-Geiger climate classification system is internationally used, however the US Department of Energy has a guide to US climate zones, and the state of California has its own specific guide to California climate zones.
Climate classification systems are useful in determining overall passive design strategies to implement, however they often do not consider microclimates. Microclimates are small areas that feature different climate characteristics from the overall climate zone they are located within. They are caused by different topographies, bodies of water, vegetation, and site surroundings. For example, San Francisco is famous for its microclimates. It can be very sunny and feel warm in some neighborhoods, while it’s foggy and cold less than a mile away. This is caused by that city’s famously hilly topography, among other factors. Also see Building Site Surroundings.