Interest in passive house construction continues to grow across Ireland, driven by rising energy costs, tighter building standards, and a broader shift towards sustainable living. For homeowners planning a new build or a deep retrofit, the passive house standard represents one of the most rigorous and effective approaches to energy efficiency available. But achieving certification depends on every element of the building envelope working together, and windows and doors are among the most critical components in that equation.
What is the passive house standard?
The passive house standard, originally developed by the Passivhaus Institut in Darmstadt, Germany, is a voluntary building performance standard focused on minimising energy consumption while maintaining exceptional indoor comfort. It is not a building type or a style of architecture. It is a measurable set of performance criteria that any building can be designed to meet.
To achieve those criteria, a building must satisfy three core requirements. Annual heating and cooling demand must not exceed 15 kWh/m² of treated floor area. The building must achieve an airtightness result of no more than 0.6 air changes per hour at 50 pascals of pressure, as measured by a blower door test. Total primary energy consumption, including heating, hot water, and electricity, must remain within 120 kWh/m² per year.
These targets are significantly more demanding than Ireland’s current Nearly Zero Energy Building (NZEB) regulations under Technical Guidance Document Part L, and represent up to a 90% reduction in heating energy compared to a typical Irish home. With the EU requirement for all new buildings to be zero-emission from 2030, the gap between standard regulations and the passive house standard is expected to narrow considerably in the coming years.
Why windows and doors are so important in passive house design
In any building, windows and doors represent the thinnest and most thermally vulnerable parts of the envelope. In a passive house, where every element must perform to an exceptionally high standard, the specification and installation of glazing becomes even more consequential.
Passive house windows must typically achieve a whole-window U-value of 0.80 W/m²K or lower. This is well beyond the minimum requirements of Irish building regulations, which currently allow replacement windows with U-values of up to 1.6 W/m²K. To reach these levels, triple glazing is effectively essential, combined with low-emissivity coatings, argon or krypton gas filling, warm-edge spacer bars, and thermally broken or multi-chambered frames.
However, the window itself is only part of the picture. Installation quality plays an equally important role. Even the highest-performing unit will underperform if junctions between the frame and wall are poorly sealed, if thermal bridging occurs around the opening, or if airtightness is compromised during fitting. In passive house construction, installation detailing is as important as product specification.
Airtightness and thermal bridging
Airtightness is one of the defining characteristics of a passive house. The 0.6 ACH target is extremely stringent, and achieving it requires meticulous attention to every joint, junction, and penetration in the building envelope. Windows and doors are among the most common points where airtightness can be compromised.
Proper sealing around window and door frames, using tapes, membranes, and compression seals appropriate to the substrate, is essential. The interface between frame and wall must be designed to maintain both an airtight and a weathertight barrier, without creating cold bridges that could lead to condensation or heat loss. The Passive House Association of Ireland provides guidance on best practice detailing for Irish construction methods.
Thermal bridging at window junctions is another area that requires careful detailing. In passive house design, windows are often positioned within the insulation zone of the wall rather than flush with the outer face, helping to maintain a continuous thermal envelope and reduce heat loss at the frame edge.
How Fairco products support passive house performance
Fairco’s window and door systems are engineered with thermal performance, airtightness, and long-term durability as core design priorities. While the passive house standard places demands on the entire building, Fairco products offer several attributes that align with these requirements.
Fairco OMNIA Flush and Performance uPVC ranges are available with triple-glazed units, achieving U-values as low as 0.75 W/m²K in the case of OMNIA Flush, comfortably within passive house territory. These systems combine insulated multi-chambered profiles, advanced gasket sealing, and precision-manufactured frames to deliver consistent thermal and airtight performance.
Fairco’s aluminium systems also incorporate thermally broken profiles, supporting low U-values while allowing for slimmer sightlines and larger glazed areas. This is an important consideration in passive house projects where solar gain and daylight are part of the energy strategy.
Because Fairco controls design, manufacture, and installation, performance is managed as a complete system rather than a collection of individual components. This is particularly important for passive house projects, where the gap between designed and actual performance must be minimised.
Ireland’s climate advantage
Ireland’s mild maritime climate is well-suited to passive house construction. Winter temperatures rarely drop to extremes, which means achieving the 15 kWh/m² heating target is more achievable here than in colder northern European countries. Ireland also benefits from useful levels of solar gain, even during winter months, which can be harnessed through carefully oriented glazing.
The Passive House Association of Ireland notes that the country has one of the largest pools of trained passive house designers and tradespeople in Europe relative to its population. Combined with increasing regulatory momentum and the SEAI’s continued support for energy efficiency upgrades, passive house construction is expected to become an increasingly mainstream approach in the years ahead.
Planning your passive house project
If you are considering building to the passive house standard, early engagement with experienced suppliers is essential. Windows and doors should be specified as part of the overall energy model, not selected as an afterthought. Factors including frame material, glazing specification, installation methodology, and orientation all influence the final energy performance of the building.
Fairco’s team can advise on product selection, U-value calculations, and installation approaches that support passive house certification. Whether you are working with an architect, an energy consultant, or managing a self-build, expert guidance on glazing and door specification helps ensure the building performs as intended.
Contact Fairco to discuss your passive house project, or explore our window ranges to understand the performance options available.
