Passivhaus in hot climates
The Passivhaus standard was initially developed for mid and northern European climates but has been proven to work extremely well in hot climates. High levels of airtightness and insulation work equally well in protecting buildings from overheating provided there is adequate solar shading.
Controlled mechanical ventilation allows options to pre cool the supply air and also to humidify or de-humidify the ambient air depending on the relative humidity. In combination these strategies are capable of significantly buffering the daytime temperature swing. Conventional cross ventilation through open windows and night purge ventilation strategies may also be used as part of the Passivhaus cooling concept when appropriate, such as during the cooler evening of a hot day.
In climatic regions where the daytime temperature does not drop low enough to purge the accumulated heat gains from the building at night there will be a residual cooling load. In such cases the Passivhaus standard permits 15 kWh/m2.yr of cooling energy to be used. A small cooling load has proven to be sufficient in almost all cases because the Passivhaus concept is highly effective in reducing unwanted heat gains.