Halifax Passivhaus, West Yorkshire

A selfbuild project, built using masonry brick and block construction, has recently been completed in Halifax and is the first certified Passivhaus projects in the Calderdale area. Designed for selfbuilder clients Graham and Sally by Architect Ian Whitworth, at Progressive near Huddersfield, and built by West End Joiners and Builders Ltd, the project was built to a tight budget of £1850/m2.

21° ran a training day for the builders and sub-contractors on the project and also undertook Passivhaus Planning Package PHPP peer review of the architect’s PHPP modelling. 21° also designed, supplied and commissioned the MVHR system at the project.

Background

After their children had grown up Graham and Sally were looking to move house and build a low energy home to settle in. They originally wanted to be part of a co-housing scheme but it ended up not being practicable for them. During their cohousing research they became convinced that that the Passivhaus low energy building standard was the way to go. Eventually they found a suitable garden plot in Halifax with planning permission.

Ian Whitworth at Progressive, a qualified Passivhaus Designer, was appointed to work on the project. The project received planning permission in December 2018 with building work starting in autumn 2019 and completing a year later.

Design

Passivhaus

The project was designed in Passivhaus Planning Package PHPP by Progressive and received Passivhaus certification in early 2022.

Final airtightness test:  0.39 ach @ 50 Pa

Cavity wall construction

21° Director Bill Butcher was consulted to discuss construction methods and key features. This led to the decision to build using conventional masonry construction, partly due to the site access at the plot. The cavity wall masonry construction has a 250mm insulated cavity with wet plaster used on the walls for airtightness, alongside Pro Clima airtightness tapes. The traditional stone front of the house is sympathetic to neighbouring houses and the local vernacular.

Shading strategy

The site is south facing with good shading offered by mature trees (with Tree Protection Orders). There are large windows to the south elevation with overhangs for shading. Graham and Sally did not experience any summer overheating problems during their first summer in the house.

Lifetime design

The house was designed to have a flexible design with 4/5 bedrooms and rooms that could change their purpose over time. The house has also been future-proofed for old age, with careful attention paid to creating a level access to the front.

Heating

Space heating for the home is provided by 2 electric radiators downstairs (3.8kwh). The roof has a solar PV system with inverter and linked to the electric car charger. Water heating for the project is provided by an air source heat pump/immersion cylinder.

Effect of COVID/ lockdown

The project was mid-build when the first lockdown in 2020 was announced. Fortunately for Graham and Sally the building contractors were able to carry on, with strict Covid guidelines in place and the adaptation of site conditions.  The building team enforced a ‘one trade at a time’ policy to minimise the risks.

Training

Graham and Sally commissioned a day’s training of the project’s builders and sub-contractors, including electricians and plumbers, at Green Building Store’s Heath House Mill base.

The training, which was led by Green Building Store Director Bill Butcher, included hands-on airtightness training, such as taping around windows, and a visit to the Kirkburton Passivhaus.

PHPP Peer review

Green Building Store’s in-house Passivhaus consultants undertook a PHPP peer review for Progressive. This is an inexpensive belt and braces approach to ensure that the PHPP calculations were correct, offering additional peace of mind for Graham and Sally.

MVHR mechanical ventilation with heat recovery

Green Building Store designed, supplied and commissioned the PAUL Novus 450 MVHR system, with rigid steel ducting, at the project.