What is EnerPHit?

written by Tracey Sludds
Modern EnerPHit extension comprising of a series to flat roofed boxes with pre cast concrete parapets and white aluminium aluclad triple glazed windows and raised planters forming balustrade to raised external terraced area.

EnerPHit is the established Standard for refurbishment of existing buildings using the Passive House basic principles and components. The Passive House Standard for new construction is not always achievable for works to existing buildings – even with an endless money pit! For this reason PHI (Passive House Institute) developed the ‘EnerPHit – Quality Approved Energy Retrofit with Passive House Components’ certification process for existing buildings.

The basic 5 principles of the Passive House Standard are still used to achieve the EnerPHit Standard; optimising (1) Thermal Insulation levels with (2) Thermal Bridge Free design, high thermal performance (3) Passive House Windows, very low air-leakage through the building (4) Airtightness levels, utilisation of passive, solar and internal gains and good indoor air quality maintained by a (5) Ventilation with Heat Recovery system with highly efficient heat recovery levels.

Diagram showing main components required to achieve the passive house EnerPHit retro-fit standard.

However, the target values for some aspects are lower than that required to achieve the Passive House Standard; for example – Airtightness target for Passive House Standard is <0.6 air changes/hr@50, while the target for EnerPHit Standard is <1.0 air changes/hr @50; similarly the targets for the Space Heat Demand & the Space Cooling Demand for a Passive House are both <15 kWh/m2.yr, while for an EnerPHit House they both are <25 kWh/m2.yr.

Similar to the Passive House Standard for new buildings, the EnerPHit Standard classes of Classic, Plus and Premium can be achieved depending on the use of renewable energy sources, along with all other common criteria; demonstrated within the Passive House Planning Package (PHPP). For more specific information on the certification criteria see Passive House Institute

With the right Passive House Designer using the Passive House Principals from the start of your design, you can minimise the need for unnecessary artificial lighting and heat, and reduce not only your CO2 emissions but you can reduce your energy bills by 75-90%

Passive house institute official logo for the three categories of the passive house certified retro-fit standard.