Read more about this longhouse style self build below
What is a Passivhaus?
The Passivhaus standard originated in Germany in the 1990s. A group of academics formalised the passive design techniques that people have been using for centuries, such as insulating to high levels and positioning homes for solar gain. In short, passive design is when you construct a home with as low a heat demand as possible.
The three cornerstone elements of Passivhaus design are:
- Insulating to a level which far surpasses Building Regulations
- The structure must be airtight (again, above Building Regulation requirements)
- There must be a mechanical ventilation and heat recovery (MVHR) system to maintain comfort and save energy
You can find out about the exact specification for a Passivhaus, including maximum U values and yearly heat demand, on the Passivhaus Trust.
Design: Looks Versus Performance?
A common misconception about Passivhaus, it that you have to compromise on the aesthetics of your home to achieve such high levels of energy efficiency. However, as the homes below show, you can build a stunning Passivhaus in both traditional and contemporary styles. And while things such as window placement may be affected, the overall look will rarely suffer.
The following homes are not all Passivhaus certified. That is to say, they meet the requirements, but have not been formally accredited. Either way, they show how to build a stunning home using passive design techniques.
A Dynamic Passivhaus Show Home
Designed by package company Potton, this new Passivhaus show home was designed using the Passivhaus Planning Package (PHPP) in association with HTA Design. Derived from a desire to flood the interior with natural daylight, a series of simple design moves creatively breaks down ‘the Passivhaus box’, employing large openings and a distinctive butterfly roof.
Central to the design is a top-lit enclosed ‘courtyard’ which sits at the heart of the building, filling the centre of the floorplan with natural daylight. A large south-facing opening on the ground floor has been maximised to benefit from solar gain, which, combined with other Passivhaus principles, helps to reduce the energy consumption of the house to 15kWh/m2/yr for heating. The roof overhang then protects this glazing from excessive solar gain and overheating of the interior during the summer, while maximising solar gain during the winter months.
The airtight building has been constructed using structural insulated panels (SIPs), is heavily insulated, and includes triple glazing and a mechanical ventilation heat recovery system (MVHR). Hot water is provided using a micro air source heat pump that is ducted to outside the property.
A Barn-Style Passivhaus
This Passivhaus in Berkshire was built by Tom Gresford of Gresford Architects using a prefabricated timber frame, constructed off site and then erected on site to airtight stage within two weeks. Clad in vertical timber panels, the exterior façade nods to the traditional agricultural buildings in the area.
“Another critical aspect of the Passivhaus way of building is that the house provides exceptional levels of internal comfort, year round. A mechanical ventilation heat recovery (MVHR) unit provides constant background ventilation. Opening triple-glazed windows and large triple-glazed sliding doors also debunk the Passivhaus myth that the house must always be closed. External blinds are also automatically deployed when the internal temperature reaches 21°C, thus reducing the chance of overheating,” explains Tom.
A Curved Passivhaus in Norfolk
Sitting within a garden plot in Norfolk, Lime Tree Lodge challenges the conventional straight-lined form of typical Passivhaus projects, as it curves its way around a protected lime tree on the site. Built by Parsons + Whittley Architects as a retirement bungalow for homeowners Rob and Jane Young, the curved design positions the tree as the central focus for both the building and the garden.
Recognising that the tree could provide shade in the summer but allow sunlight through in winter, the opportunity for a large south-facing glazed wall for the sitting room, together with the client’s request for a low-energy building for their retirement, all led to the early adoption of the Passivhaus standard.
Built using masonry construction – selected as a result of labour availability and thermal mass – the property features brick cladding to the street-facing elevation which complements the adjacent inter-war and 1980s buildings. Siberian larch provides a softer aesthetic on the rear façade. Large overhangs on this south-facing elevation also provide protection against overheating.
“Curved buildings are usually more complex builds,” says Chris Parsons of Parsons + Whittley Architects, who have completed over 60 Passivhaus projects to date. “Fortunately, the vertical timber cladding meant it was relatively straightforward to create the curve — the only real challenge was the zinc roof, with the zinc panels needing to be tapered to the roof. Insulation, triple glazing and mechanical ventilation make it a comfortable place to live.
A Low-Energy Masonry Passivhaus
After a four-year planning battle, Angela and Paul Dallas managed to self build their low-energy Passivhaus with the help of Green Building Store. Externally, the project has been finished in stone, which suited the cavity wall construction method — the use of a cavity wall also sat well within the comfort zone of the builders in the area. Cedar cladding adds interest and helps to break up the façade.
“The only sticking point in the design was the large full-height glazed bay window,” explains Bill Butcher of Green Building Store. “A Passivhaus usually performs better when the elevations are flat, but given that the house is relatively large the building is able to cope with it. The bay section was originally meant to be ashlar cut stone, but this wouldn’t have worked with Passivhaus because of the thermal bridging. The new glazed bay has triple-glazed timber windows with a powder-coated aluminium façade, insulated with polyurethane.
“It’s comfortable, the fuel bills are minimal, and we receive £135 a quarter back from the Renewable Heat Incentive,” says Angela. “Because Passivhaus is so efficient, the house doesn’t require all sorts of expensive eco technology which has the potential to break down. It’s very solid, quiet and comfortable. The MVHR is circulating air all the time and the atmosphere is always pleasant. The house has far exceeded my expectations from a comfort level — it’s a joyful home to live in,” says Angela.
This home was built in just four months as a turnkey project by German manufacturers Hanse Haus. The owners originally had plans to extend and update their draughty 1930s home, but realised it would be as cost-effective to build a new, highly efficient home instead. Building to Passivhaus standards has also given them incredibly low fuel bills and a constant internal temperature.
Despite the planning constraints of building in an Area of Outstanding Natural Beauty, they have managed to create a stylishly modern home. White rendered walls have been paired with a zinc roof, and large areas of glazing with external blinds for shading.
This contemporary Passivhaus was built on a sloping site in the Scottish borders. The home features a stone-clad frontage with a cedar-clad, glazed elevation to the rear. A roofstrip of glazing along the length of the building floods the interior with natural light and forms a glass division between the north and south elevations.
Due to high levels of insulation and airtightness, the only used source of heat in the house is a woodburning stove. Underfloor heating has been installed in the two bathrooms but has never been used — even when temperatures dropped to -16°C one winter. The owners have even included a special cat flap and letterbox to maintain airtightness.
This carbon negative home was built mostly from materials sourced from the 300-acre farm it sits on. Cladding was made from wind-felled oak tress and the dry stone wall from 500-tonnes of rock collected from the land. Turf from the site covers the Sarnafil flat roof, helping it camouflage with the landscape.
Layout has been influenced by passive solar gain, with the stunning views enjoyed through triple glazed windows. The 150mm thick sheep’s wool insulation has been shorn from the owners’ flock. A biomass stove, situated in the heart of the home, heats the interior stone wall, evenly distributing warmth.
This Somerset Passivhaus has been clad in wood to help it blend with the slope it is built into. The roof overhangs to provide summer shading to the large windows and verandas. This results in a form that echoes the local agricultural buildings.
The home is highly insulated and airtight. It has also been built using a vapour permeable wall construction that moderates humidity and works with the MVHR system to create a healthy internal atmosphere.
A Farmhouse Passivhaus
Positioned on an isolated site in the North Pennine Area of Outstanding Natural Beauty (AONB), Steel Farm Passivhaus has been built using traditional masonry construction with the design taking the form of a modern-day farmstead, clad in stone under a slate roof.
Built on a site without mains gas, the home – designed by Mark Siddall of LEAP: Lovingly Engineered Architectural Practice – is heated with small gas cylinders topped up with solar thermal panels for domestic hot water. AECB’s (Association for Environment Conscious Building) water standards informed the design and have minimised the demand for domestic hot water without compromising comfort. There’s also a reed bed system for the treatment of foul waste water.
Triple-glazed timber windows and doors from Green Building Store and a mechanical ventilation heat recovery (MVHR) system complete the project.
Each year Steel Farm has taken part in the International Passivhaus Open Day event, members of the public get to experience what a Passivhaus is really like. You can watch the popular documentary about the house, and get the opportunity to visit the Steel Farm, at passivhaussecrets.co.uk
Both passive and active eco features have been incorporated into the design of this Oakwrights home in Gloucestershire. The house has been set into the slope, with a large basement level that keeps the external volume of the home to a minimum, reducing heat loss.
The home has then been orientated so that significant areas of glass face south. Eco features are complemented by the use of untreated Siberian larch and a sedum roof for an organic look.
Built to replace an old cottage, this modern take on a rural longhouse is just one room deep. Glazing is limited on the northern elevation, with south-facing glazing bringing light (and warmth) into the home.
The house has been built using an innovative blockwork system – with 100mm of internal insulation blockwork – achieving a U value of just 0.12. The walls have been coated in a crisp white render, but the overall look takes cues from the local vernacular.
Historic building materials have been paired with modern construction methods in this traditional style home with high energy efficiency. The owner is well known in building conservation circles, so it came as some surprise when he swapped their 17th century brick and flint home for a new build. However, the new home has an average heat demand of just 2.5kW, costing only £1.25 a day to run.
The combination of 300mm hemp/lime and hemp-fibre walls gives a U value of just 0.13. The walls are also vapour-permeable to regulate humidity and create a comfortable environment, which can be hard to achieve in such well-insulated, airtight homes.