Winning the Newbattle for Passivhaus!

The Morris Road new build development of 20 housing blocks providing 90 new affordable homes in Newbattle in Midlothian has just received Passivhaus certification. It represents a next key step in Midlothian Council's ambitious Passivhaus social housing programme.

Occupying the former Newbattle High School playing fields, this residential development includes 90 Passivhaus certoified affordable homes for rent for Midlothian Council. The design focuses on the creation of highly energy efficient homes with low running costs for residents, which are interspersed amongst large areas of shared and public open space, private gardens and landscape spaces.

The development has a low-density layout comprising short terraces and semi-detached houses, responding to the site’s spatial constraints. The requirement for a lower density, more suburban character and less compact building form presented additional challenges in achieving the high levels of energy efficiency required by Passivhaus. The homes are designed with a high-performance building fabric to minimise heat loss and optimise energy use. Variations in orientation, layout, and surrounding context mean that each of the 20 housing blocks responds slightly differently to solar gain and shading, resulting in a carefully balanced and diverse development.

The project was designed by PHT member Smith Scott Mullan, with PHT Patron ECD Architects as Passivhaus designers, PHT member Carbon Futures offering Energy Consultancy and PHT member Ogilvie Construction as main contractor. The project was certified by PHT Patron WARM.

Key stats

Construction: Timber frame
Number of homes: 90
Form factor: 2.69 (Block 5 example)
Commenced: 2023
Completed: 2025
Certified: Passivhaus, 2026

Newbattle Passivhaus social housing under construction. Image credit: ECD Architects

Newbattle Passivhaus social housing. Image credit: Paul Zanre Photography

We modelled each of the 20 housing blocks individually in the Passivhaus Planning Package (PHPP). While there are similarities in design and layouts, there are inevitable variations in surrounding shading, so that the solar gains of each building are slightly different.

During the scheme value engineering phase, we assessed the project proposed changes using the PHPP model. From this, we were able to provide robust, quantitative information on the impact of each option. This ensured that only changes with a neutral or positive effect on energy efficiency were taken forward, maintaining the performance of the scheme.

Dilveer Kaur Hoonjan, Passivhaus Designer, ECD Architects

Construction

Timber frame construction is used throughout, with a strong emphasis on continuity of insulation and the reduction of thermal bridging to ensure consistent performance across all dwellings. The low density nature of the scheme created some Passivhaus challenges and a deep timber kit wall construction using engineered joists was needed to meet the U-values required.

As the scheme has progressed, design refinements needed to be carefully managed to maintain energy performance while responding to practical and economic considerations.

We are delighted to be providing these warm, comfortable, high performance homes to our residents/tenants. This project demonstrates the Council’s commitment to be carbon neutral by 2030 as outlined in the Council’s Climate Change Strategy.

Neil Davidson, Midlothian Council

U-values

Roof: 0.066 W/m²K

Timber frame

Wall: 0.092 W/m²K

Timber frame

Floor: 0.54 W/m²K

Insulated concrete slab

Newbattle Passivhaus social housing. Image credit: Paul Zanre Photography

Building performance

Designed & actual energy performance

Based on Block 5 as an example

DESIGNED

ACTUAL

Airtightness n₅₀ (≤ 0.6ACH @ 50 Pa)

0.56 @ 50 Pa

Space Heating Demand (≤ 15 kWh/m².a)

13 kWh/m².a

12 kWh/m².a

Heating Load (≤ 10 W/m²)

8 W/m²

7 W/m²

Primary Energy Demand (≤ 120 kWh/m².a)

85 kWh/m².a

87 kWh/m².a

Primary Energy Renewable (PER) Demand (≤ 60 kWh/m².a*)

87 kWh/m².a

68 kWh/m².a

Primary Energy Renewable Generation

9 kWh/m².a

15 kWh/m².a

*+/-15 kWh/m².a allowance if offset by energy generation. See Passivhaus criteria.

Ogilvie Construction is wholly committed to helping drive the transition to net zero across Scotland's built environment, and Passivhaus technology is central to that ambition. The Morris Road project at Newbattle demonstrates that ultra-low-energy housing is not just achievable at this scale, and with this housing typology, but can be delivered to the highest standards of quality and comfort. We intend to be at the forefront of Passivhaus innovation, and projects like Morris Road give us both the expertise and the conviction to lead the roll-out of this technology across the sector.

Martin Poole, Precoonstruction Director, Ogilvie Construction

Services

The building services strategy focused on a highly insulated, airtight fabric paired with efficient electric systems to meet local sustainability

Heating & Hot Water: Direct electric panel heaters and dedicated electric-only showers were specified, supported by a 120L thermal storage hot water cylinder.
Ventilation: A mechanical ventilation with heat recovery (MVHR) system was specified for each home.
Summer comfort: Passive design and external shading were used to optimise summer comfort in the homes.
Renewables: Roof-mounted solar photovoltaic (PV) panels (minimum 420W per panel), with any excess electricity generated exported back to the grid.

Newbattle Passivhaus social housing. Image credit: Paul Zanre Photography

Challenges & lessons learned

Low density: The form factor of the homes was higher than for more high density project . This has led to the need for an extremely high performing thermal envelope and deeper frame timber frame construction with lower U-value requirements and a thermal bridge free design to meet the Passivhaus performance requirements. Close collaboration with the structural engineer and timber kit supplier helped optimise the buildability of the envelope.
Deeper timber frame: The project team has worked closely with the architect and contractor to ensure that the timber frame construction achieves the specified U-values and is free of thermal bridging. It was necessary to incorporating psi values from the thermal bridge modelling into the PHPP (Passivhaus Planning Package), ensuring that the model accurately reflects actual heat loss and real-world performance.

Inspections: A key success was the higher frequency of holding point inspections compared with a typical non‑Passivhaus scheme, something that will be taken forward by the contractor into future projects. These inspections were scheduled at each construction stage and carried out with subcontractors and Midlothian Council. The inspection programme was intensive but proved valuable and fostered trust and transparency throughout the project.
Passivhaus training: All six construction managers working on the project underwent Passivhaus training and gained Passivhaus tradesperson certification.
Evidence gathering: The Passivhaus approach to evidencing works - requiring significantly more detailed recording and documentation and recording building elements both packaged and unpackaged at every key stage through to completion - is a practice the contractors are carrying forward into current and future projects. The construction team has recognised the wider value of this enhanced documentation in supporting future project queries, whether or not the scheme is Passivhaus.

There was nothing more rewarding than getting the certification and the Passivhaus plaque, confirming we have met and achieved the brief.

Brian McGuinness, Senior Project Manager, Ogilvie Construction

Newbattle Passivhaus social housing. Image credit: Paul Zanre Photography

Architect’s view

The teamwork on this project has been phenomenal. The entire design team has worked closely with Midlothian Council and Ogilvie Construction to deliver outstanding homes that will stand the test of time and contribute positively to alleviating the Climate and Housing Emergencies we currently face.

At a technical level most of the key Passivhaus elements are contained within the innovative timber kit design, which we have worked hard to optimise in terms of thermal performance, buildability and cost. We intend to use variations on this construction type for future Passivhaus projects to bring best value for our Clients.

Graham Acheson, Director, Smith Scott Mullan

Key team

Architect: Smith Scott Mullan
Passivhaus Designer: ECD Architects
Contractor: Ogilvie Construction
Structural engineer: Bayne Stevenson Associates
Energy consultants: Carbon Futures
M&E Design: Hawthorne Boyle
Landscape Architect: SLR Consulting
Passivhaus Certifier: WARM

Newbattle housing development. Image credit: Midlothian Council

Delivering Passivhaus at scale is not about treating each development as a standalone project. As Midlothian Council's growing programme demonstrates, every scheme provides valuable lessons that can be carried forward, from design optimisation and quality assurance to construction techniques, procurement and collaboration across the supply chain. Building on experience helps reduce risk, improve efficiency and strengthens confidence for future projects.

As more local authorities and housing providers adopt the Passivhaus standard, sharing these lessons becomes increasingly important. Join the conversation at this year's Passivhaus Conference this November, where councils, housing associations and project teams from across the UK will share their experience of delivering Passivhaus at scale. Or become part of the Passivhaus Client Clubs, bringing clients together to exchange practical knowledge, learn from completed projects and accelerate the delivery of high-quality, low-energy homes.