Term: EnerPHit

The Passivhaus Institut’s energy performance standard for retrofits. It allows a maximum annual [specific] space heated demand of 25kWh/m^2.a and an upper airtightness limit of 1.0ACH, if the 0.6ACH target can be shown to be impracticable, and also sets requirements for individual elements of a retrofit, should the 25kWh/m^2.a requirement not be met. Only retrofits in certain climates, including central Europe and the UK, can be certified to the EnerPHit standard.

Source: The Passivhaus Handbook