A selection of PH15 projects showing how versatile the PH15 system is in transforming different design ideas and project types into Passivhaus reality.

Northenhay, Totnes

Bespoke new build detached house (treated floor area, 205 sqm), concept design by Studio DC Architects, and then detailed to the Passivhaus standard by PHH using the PH15 System. Construction will start end of 2018.

External finishes are a mix of lime render and vertical timber boarding. Zinc pitched roofs with first floor terrace to side. Windows and doors Katzbeck CombinaPassiv range.

Passivhaus statistics:

TFA 205 m² Building Form Factor 3.0 with average wall U-value 0.11 W/m²K, floor 0.078 W/m²K, roof 0.096 W/m²K, and average installed whole window/door U values 1.0 W/m²K.

GFA circa 230m²,

On site 2018


Northenhay concept design
PH15 timber frame design

Dart House, Devon

Bespoke new build detached house (net floor area 298sqm) on a sloping site, designed to planning stage by Passivhaus Homes and then detailed  using the PH15 System. Construction started on site March 2018 by Waterhead Projects.

External finishes are a mix of lime render and western red cedar boarding. Windows and doors Katzbeck CombinaPassiv range.

Passivhaus statistics:

TFA 270.1 m² Building Form Factor 3.93 with average wall U-value 0.093W/m²K, floor 0.11W/m²K, roof 0.083W/m²K, and average installed whole window/door U values 0.89W/m²K.

GFA 298m²,

Construction by Waterhead Projects


Dart House front elevation

Riverways, Devon

Bespoke new build detached house (net floor area 208sqm) designed to planning stage by architect Chris Donoghue and then detailed and constructed using the PH15 System – the design needed some modifications by us to hit the Passivhaus standard. Construction started on site April 2015 by Passivhaus Homes Ltd.

External finishes are a mix of lime render and western red cedar boarding. Windows and doors Katzbeck Linea range.

Passivhaus statistics:

TFA 193.8 m² Building Form Factor 2.79 with average wall U-value 0.09W/m²K, floor 0.11W/m²K, roof 0.10W/m²K, and average installed whole window/door U values 0.88W/m²K.

GFA 208m²,  PH15 System components £115,000

Constructed by Passivhaus Homes Ltd
Completed Spring 2016.

Certified Passivhaus

Riverways front elevation

Akerman Rd, London SW9

This is a project for Lambeth Council for three new Passivhaus terrace houses. The site is an urban infill on a typical London street. The design is by Anne Thorne Architects and we have completed the working drawings to construct using our PH15 System. The project included 6 retrofit flats which have been detailed by Prewett Bizley Architects. Finishes are a mix of lime render, brick entrance porches, brick slips and reconstituted slate roofs. This project is the first collaborative project for the 15-40 Architecture Collective and our first use of the PH15 kit for social housing provision.

Passivhaus Statistics:

TFA 371sqm

Form Factor 1.8, with U-values of roof 0.108W/m2K, walls 0.105W/m2K floor 0.106W/m2K.  Heating load 7.9W/m2. Predicted Heating demand 9.1 kWh/m²a

Airtightness test results:0.34, 0.39 and 0.4 ach

Construction by Sandwood Construction Ltd

Completed December 2016

Certified Passivhaus


Littlepits Passivhaus (Plus)

A five bedroom detached house. The design had to meet the exacting Chiltern’s Design Guide, addressing planning concerns on visual impact within its Green Belt setting. The house is a mix of lime render, brick slip with lime mortar, and oak feather edge cladding. There are also two traditional green oak verandas. The house incorporates a ‘Glatthaar’ basement system which is within the Passivhaus envelope. Littlepits is now one of the most airtight houses in the UK at 0.07 ach@50Pa.

Passivhaus Plus Statistics:

TFA 317sqm

Form Factor 2.43 with average wall/roof U value 0.085W/m2K, floor 0.07W/m2K, average whole window/door U values from 1.02-0.85W/m2K. Heating demand 11.1 kWh/m²a, heating load 7.3 W/m2. Final air-tightness result 0.07 ach@50Pa. PV: 7kW peak array.

Construction by Jigsaw Design and Construction Ltd.
Completed December 2017.

projects at the beginning - view of plans

Ha Ha House, Torquay

Designed by architect Richard Maddock for his own home, this is a single storey modern design sited in front of an old stone retaining wall, creating a striking juxtaposition of old and new.

Passivhaus Homes collaborated on modifications to the original design to bring it up to Passivhaus performance standards, and then detailed the construction package using our PH15 System.

External finishes are lime render and wood cladding with a living roof. Windows and doors are Katzbeck Linea.

Passivhaus Statistics:

TFA 133sqm

Form Factor 4.1, with U-values of walls and roof 0.076W/m2K, floor 0.071W/m2K.  Heating load 9.8W/m2. The single storey design makes getting to Passivhaus a challenge (see the poor form factor), but good junction details achieved by the PH15 System resulted in negative linear cold bridges.

GFA 139m², PH15 System components £79,000

Completed Autumn 2016. Construction by Passivhaus Homes Ltd.

Ha Ha artists impression

Summertown, Oxford

Bespoke new build detached house (gross internal floor area 372 sqm), a contemporary design by Passivhaus Homes and to be built using the PH15 System. It has been PHPP energy modelled so that it could be certified as Passivhaus Plus subject to photovoltaic array being installed.

External finishes are a mix of silicate render and EQUITONE (linea) cladding. Windows and doors Katzbeck DESIGN range.

Passivhaus statistics:

TFA 366 m² Building Form Factor 2.0 with average wall U-value 0.098 W/m²K, floor 0.08 W/m²K, roof 0.08 W/m²K

GIA 372 m²



Summertown Planning 3D

Tring Passivhaus, Chilterns

This detached 3-bed house (net floor area 122sqm) is to be built in the rear garden of a house in the High Street Conservation Area in Tring town. The house is a modification of our generic 3-bed house using the Passivhaus Homes PH15 System. External finishes are a mix of lime render, timber cladding with plain clay tiling on the roof with oak end rafters. Specification includes a Lacuna folding/sliding screen door and Katzbeck windows.

Passivhaus Statistics:

TFA 110sqm

Form Factor 3.2 with average U-values of walls and roof 0.08W/m2K, floor 0.07W/m2K. Space heating demand 13.6kWh/sqm.a.
GFA 122m², PH15 System components £79,917
Initial air test result 0.3 ach

Completed summer 2016. Construction by RAK Construction Ltd

Certified Passivhaus


Completed house viewed from the High Street

Camden NW5

Two new dwellings designed to planning stage by Bere Architects on a small site previously occupied by 6 lock-up garages. The project has a poor Form Factor (4.3), due to the many design constraints of this site, making it more expensive and challenging to meet the Passivhaus standard. The clients therefore decided to target the Passivhaus Institute Low Energy Building Standard which allows a heating demand between 15 and 30 kWh/m²a rather than the stricter full Passivhaus standard of below 15 kWh/m²a.

Passivhaus statistics:

TFA : 148.5m²
Form Factor 4.31, with U-values of walls 0.078W/m²K, roof 0.104W/m2K, floor 0.12W/m2K.  Heating load 12W/m2.
Heating Demand 25 kWh/m²a


Currently under contruction

Camden Frame

Berrydown, Mid-Devon

A three bedroom detached Passivhaus using an innovative ‘portal frame’ design eliminating thermal bridges at the first floor, eaves and ridge using a simple construction method. The innovative timber portal frame construction removes the need for a central ridge beam (simplifying air-tightness details), and enables fully filling of the walls and roof as a single element. The first floor is hung off a ring beam fixed back to the portal frame members. This removes any thermal bridging at the wall/floor junction and again simplifies construction of the air-tight layer. The building design meets the clients contemporary design preference for a minimalist eaves detail while also reflecting the local barn vernacular in this region of mid-Devon. This is a contemporary Passivhaus for a young family suitable for its Conservation setting in an English rural village.

Passivhaus Statistics:

TFA 113sqm

Form Factor 3.29, with U-values of floor 0.07W/m²K; wall 0.09W/m²K; roof 0.10W/m²KDesign space heating demand: 13.8kWh/m² per annum; heating load 9.3W/m²

Completed July 2013.

the finished house viewed from the hill
frame under construction
cladding finished
window close-up
Finished house from the road

Totnes Passivhaus

One of the UK’s first Certified Passivhaus refurbishment projects being a hybrid retrofit with new build extension achieving the full passivhaus standard. The extension is made from timber frame, uses recycled newspaper insulation and has a living roof. The house also has a photovoltaic array and solar hot water panels. The design achieves below the 15kWh/sqm requirement for space heating (90% less than the average UK) Total Primary measured energy in use is 75.8KWh/sqm.a The project was completed in July 2011 – the final air tightness test was an impressive 0.19 ach at 50 Pa (Passivhaus standard is 0.6 ach). This makes Hunters Moon the most leak free retrofit house in the UK!

Passivhaus Statistics:

TFA 162sqm

Form Factor 2.62, with U-values of walls and roof 0.01W/m2K, design space heating demand: 13.3kWh/m² per annum; heating load 9.3W/m².


Completed 2011

Certified Passivhaus and Winner of the 2013 Passivhaus Trust Awards

The entrance and glass canopy
Winners of the 2013 Passivhaus Trust Awards
view across the living roof
general view of house
North elevation
RIBA logo
Passivhaus Trust Member
15 40 architecture collective
certified passivhaus consultant