- Well insulated building envelope - adding external insulation to walls to reach u-values of 0.1 W/m2K for walls and roofs.
- High energy performing windows and doors - perhaps triple glazed windows.
- Minimised heat loss through thermal bridges (i.e. un-insulated joint sbetween walls, floors/walls, ceilings/adjacent walls, windows/walls, etc) - adding insulation where thermal bridges can occur.
- Significantly reduced structural air infiltrations, eliminating cold draughts and associated comfort losses. Passivhaus Standard is reached when there are less than or equal to 0.6 air changes per hour @ 50 Pascal pressure.
- Optimal use of passive solar and internal heat gains - south facing windows, boiler located within the building envelope, etc.
- Introduce renewable energy technologies such as solar thermal heating.
As more people elect to retrofit to Passive House Standards, the costs will no doubt reduce. Currently, the costs associated with retrofitting to Passive House Standard are estimated to be an additional EUR80-150 per square metre, or an additional 10-15% onto the cost of retrofitting to current building standards.
The benefits of retrofitting to Passive House Standard include:
- Thermal comfort equivalent to a conventional new dwelling
- Improved air quality due to the ventilation system
- Drastically reduced energy bills
- Significantly improved air-tightness
- Elimination of structural damage due to thermal bridges and mould problems
SEAI has published detailed guidelines on how to retrofit to Passive House Standard.
To assist towards some of the cost of your Passive House Retrofit there are grants available: