As the construction industry works towards Net Zero targets and stringent energy efficiency standards, Passivhaus is becoming a key consideration for developers, architects and specifiers seeking to create high-performance buildings.
Passivhaus developments require carefully selected building services that complement their low-energy design principles. Heating systems are a particularly important consideration as they must deliver efficient, consistent warmth without compromising the overall performance of the building.
In this blog, we explore what Passivhaus is, why it is gaining momentum across the UK and how underfloor heating can help support the delivery of comfortable, energy-efficient and future-ready developments.
What is Passivhaus?
Passivhaus – or Passive House in English – is a voluntary performance standard which incorporates a whole-building approach to constructing new homes that are Net Zero-ready, or optimising existing buildings to suit a decarbonised grid and enhance occupant comfort.
The aim is for Passivhaus buildings to use little energy for heating and cooling, making them ultra-energy-efficient, comfortable and healthy spaces which minimise their carbon footprint.
According to the UK government’s Housing and Net Zero report, published in July 2024, emissions from residential buildings accounted for a fifth (20%) of greenhouse gas emissions in the UK in 2022.
So, with the UK’s target of reaching Net Zero by 2050 getting ever closer, reducing the carbon emissions of our building stock is a higher priority than ever.
With Passivhaus’ whole building approach, energy efficiency is built into the design from the start, rather than included as an add-on, making it an ideal solution to building future-proof, Net Zero-ready homes.
This includes considering climate, location, building fabric, building services and more, from the earliest stage in the build programme.
There are three core principles to help buildings meet energy standards and real-world performance expectations:
- Performance and comfort criteria – clearly defined and evidence-based
- Passivhaus Planning Package (PHPP) – for energy balance calculations and comfort assessments
- Quality assurance – independent and impartial verification and certification
This is supported by five building principles, including:
- High-performance insulation – for comfort, energy demand and the climate zone
- Airtight layer – to minimise heat loss and draughts and increase longevity of materials
- Minimised thermal bridges – to prevent cold spots and mould
- High-spec windows – to keep the heat inside and provide shading
- Mechanical ventilation – which is quiet and efficient to improve indoor air quality
Buildings constructed in line with these principles result in Passivhaus structures which are well built, with no draughts, the right temperature in winter and summer, have high air quality indoors and produce low energy bills.
The Passivhaus Trust states that, as of February 2025, approximately 1% of all new homes under construction are built to the Passivhaus standard.
How does underfloor heating fit?
Passivhaus buildings are constructed with exceptional insulation and ventilation but do require some heating, typically at lower levels than traditional homes.
However, to ensure the system meets Passivhaus standards, it must be low-carbon and energy efficient.
Underfloor heating is an increasingly popular choice for Passivhaus developments.
Operating at much lower flow temperatures than traditional radiator systems, it complements the low-energy principles of Passivhaus design and works efficiently alongside renewable heat sources such as air source and ground source heat pumps.
The large heated floor area allows heat to be distributed evenly throughout the space, maintaining stable internal temperatures without creating hot and cold spots.
This gentle radiant heat also contributes to occupant comfort, reducing air movement, draughts and mould for enhanced air quality and better health and wellbeing for occupants.
For many Passivhaus projects, careful system design is essential. As heating demands are much lower than in conventional buildings, the output of the underfloor heating system and potential heat losses must be considered.
This requires detailed heat loss calculations, appropriate pipe spacing or cable selection and responsive controls to ensure the system performs efficiently without overheating the space.
Whether specified in new-build homes, apartments or commercial buildings built to Passivhaus standards, underfloor heating provides an effective, energy-efficient solution that supports the overall performance of the building while delivering excellent thermal comfort for occupants.
Case study: underfloor heating for a Passivhaus-standard project
We recently worked on a Passivhaus-standard development – Hartopp Point and Lannoy Point in Hammersmith.
A regeneration project, the development involved replacing two 1960s tower blocks with three residential buildings ranging from three to seven storeys, delivering 134 new energy-efficient homes.
We were involved in the development from early in the programme to provide expert project management and underfloor heating system design, operating within a compressed timescale to align with tight construction milestones and Passivhaus performance requirements.
Working with the main contractor and sustainability consultants, we ensured that the underfloor heating interfaces with air source heat pumps and the high-performance building fabric was optimised early in the build process.
We delivered a wet underfloor heating system in screed, which provides reliable, low-temperature heating across the mix of shared ownership, private sale and affordable rent units in the development.
The result was a Passivhaus-compliant project which also supported operational Net Zero carbon targets and reduced heat loss.
Supporting Passivhaus projects
As the industry moves towards more energy-efficient buildings, underfloor heating will continue to play a central role in delivering comfortable, efficient and future-ready homes.
At Gaia, we are working closely with housebuilders, developers and design teams across the UK to support all kinds of developments, including Passivhaus projects.
With extensive experience in both wet and electric underfloor heating systems, we provide full design, supply and installation support across residential and commercial developments.
Get in touch with the Gaia team to find out how we can support your next project.
