Dundashill - Scotland's largest Passivhaus residential project

Residents at Dundashill Platform 3, Scotland's largest Passivhaus certified residential project to date, are already experiencing the benefits of Passivhaus comfort and low energy bills. Post-occupancy monitoring on the West of Scotland Housing Association (WSHA) project highlights lower energy bills, stable indoor temperatures, and better air quality. Ongoing performance monitoring confirms that energy use closely aligns with the Passivhaus design targets.

The 90-home project has been built at a canal-side location on the former Diageo Distillery site at Port Dundas in Glasgow, and includes a range of 1-3 bedroom apartments at mid-market rent. Platform 3 is the first completed development that is part of wider masterplan to regenerate the area.

Dundashill Platform 3 comprises a series of 3 four-storey blocks and a seven-storey landmark building that are predominantly south-facing and arranged around landscaped courtyards. The design concept is based on a modular flat unit (6.5m x 14m) repeated to form a simple, compact structure. Key passive design strategies, such as building orientation, form, and glazing ratios, were central to shaping the scheme.

Interestingly east-facing Block B2, located at an angle to the other south-facing blocks, performed slightly differently to the other blocks, despite having almost identical specification and U values. It was Passivhaus certified using the heating load rather than the space heating demand criteria.

Dundashill Platform 3. Image credit: Collective Architecture

One of the highlights is that my energy bills are really low, which is night and day from my previous home.

Resident, Dundashill Platform 3, Glasgow

Designed by PHT member Collective Architecture, certified by PHT Patron WARM, the project has set out to be a resilient, low-energy development supporting long-term affordability and carbon reduction.

Key stats

Construction: Modular close-panelled timber frame and masonry blockwork
Number of homes: 90
TFA: 3210 m² (Block A), 2547 m² (Block B1), 1265 m² (Block B2)
Build start date: 2022
Completed: 2024
Certified: Passivhaus, 2024

Dundashill Platform 3. Image credit:Collective Architecture/ Keith Hunter Photography

It's one of the best developments we've ever done. For us as a housing association probably the key success is having new tenants move into these properties who absolutely love it. Taking on Passivhaus is a challenge. We know what the challenges are and have learned the lessons. It's important for us that we share those lessons with the rest of the sector.

Brian Gannon, Chief Executive Officer, WSHA

Construction

Dundashill Platform 3. Image credit: Collective Architecture

The project was built using modular close-panelled timber frame construction and masonry blockwork, with a concrete brick facade to evoke the site's whisky distilling heritage. Some of the blocks are built using masonry cavity wall at ground and 1st floor level. The contractor's offsite-manufactured iQ Timber System was specified to achieve high standards of quality control, rapid construction, and reduced embodied carbon. Manufactured in the contractor’s own factory, the project’s timber frame was delivered as a long, closed-panel kit. A key innovation in this project was the decision to install airtightness measures and triple glazed windows, which were produced in collaboration with a window supplier, directly onto the modular units within the factory rather than on site. This helped reduce the risk for project delivery and helped ensure quality control during construction.

Embodied carbon

While a full whole life carbon analysis has not been carried out, embodied carbon was carefully considered during the design process and influenced key decisions. The homes are for the main part constructed using offsite-manufactured panels made from sustainably sourced timber under zero-waste factory-controlled conditions. The timber frame panels were produced just 11.7 miles away from the project, significantly reducing the carbon footprint associated with their transportation. Utilising off-site Modern Methods of Construction further enhances construction efficiency and reduces site waste. The modular flats use a cross-wall system, which allows for potential reconfiguration of internal layouts in the future, ensuring the building remains functional and relevant as resident needs evolve over time, contributing to the longevity of the project.


U-values
Roof	Wall	Floor
0.083 W/m²K	0.147 W/m²K 0.205 W/m²K	0.378 W/m²K 0.496 W/m²K [Block B2 0.422 W/m²K]

Building performance

Dundashill blocks. Image credit: Collective Architecture

Designed energy performance
	Block A	Block B1	Block B2
Airtightness n₅₀ (≤ 0.6ACH @ 50 Pa)	0.6 @ 50 Pa	0.6 @ 50 Pa	0.6 @ 50 Pa
Space Heating Demand (≤ 15 kWh/m².a)	14.45 kWh/m².a	13 kWh/m².a	18 kWh/m².a
Heating Load (≤ 10 W/m²)	9.84 W/m²	9 W/m²	9 W/m²
Primary Energy Demand (≤ 120 kWh/m².a)	128 kWh/m².a	122 kWh/m².a	137 kWh/m².a
Primary Energy Renewable (PER) Demand (≤ 60 kWh/m².a*)	53 kWh/m².a	50 kWh/m².a	57.7 kWh/m².a
Primary Energy Renewable Generation	36 kWh/m².a	36 kWh/m².a	27 kWh/m².a

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

My energy bills are only £41 per month, this is over £150 less than my energy bill from my last home. This extra income has really helped with the cost of living increases.

Resident, Dundashill Platform 3, Glasgow

Services

Dundashill Energy infographic. Image credit: Collective Architecture

Heating & hot water: The project is all-electric with no connection to the mains gas network, in line with the project's goal to reduce reliance on fossil fuels. Compact electric back-up radiators provide occasional top-up heating. Hot water is supplied by hot water heat pumps and cylinders in the lower blocks, with the seven-storey building using cylinders connected to an Economy 7 tariff, enabling tenants to take advantage of lower-cost overnight electricity for water heating. The hot water heat pump cylinders are connected to the solar PV arrays to utilise renewable generation during the day.

Ventilation: MVHR (Mechanical Ventilation with Heat Recovery) systems deliver filtered fresh air throughout each flat, reducing heat loss while improving indoor air quality.

Renewable energy: Solar-generated electricity is provided by a 105 kWP rooftop PV array, and supplemented by mains electricity. Solar PV is connected to hot water heat pumps and cylinders in the lower blocks.

Summer comfort strategy: To address the risk of overheating, the building incorporates a range of passive design strategies. These include careful orientation, high-performance glazing, and shading from balconies. Block A and Block B1 are positioned to maximize solar gain in the winter, with their south-facing facades, while large overhangs and the design of the balconies offer shade in the summer.

We've never really put our heating on, so our energy bill are fairly low. I don't think we'll need to have the heating on that often.

Resident, Dundashill Platform 3, Glasgow

Challenges & lessons learned

Dundashill thermal image. Image credit: Collective Architecture

Project team collaboration: A collaborative and learning-focused approach was central to the project's success. The design team worked closely with contractors and site operatives through a structured, knowledge-sharing process. Toolbox talks, workshops, and detailed quality control procedures, including phased airtightness testing ensured the design quality required for Passivhaus certification was consistently achieved.
Off-site airtightness measures: The contractors de-risked delivery by installing airtightness measures in the factory rather than on site. This sped up delivery and has been one of the key technical lessons to take forward from the project.
Ensuring access for regular maintenance of each flat: The hot water heat pump system needed careful consideration to enable the systems to be maintained without regular disruption to the residents. Locating these systems in the core was the optimal solution but did need careful coordination and setting out.
Accounting for differential structural movement between the timber frame and concrete structural core: Adapting the airtightness strategy and developing solutions to take account of the settlement of the timber frame over time, and ensuring the integrity of the airtight line and the penetration of services through the walls was a key project challenge.

4-stage air testing: To verify performance throughout construction, four air pressure tests were scheduled at key stages. Test 1 was undertaken at completion of timber frame, after the installation of the airtightness layer and windows and doors. Test 2 was undertaken after completion of masonry blockwork and after first fix. Test 3 was undertaken after services were installed and before fixtures and fittings. Test 4 was undertaken on completion and for certification. Each test was conducted using a consistent internal volume (Vn50), representing the final completed building, to ensure reliable, comparable results.
Monitoring: Data loggers have been installed in 27 properties to monitor internal temperature and relative humidity. This data will support seasonal performance analysis, with planned distribution of detailed winter and summer occupant feedback questionnaires. Additionally, one-on-one interviews have been undertaken to gather qualitative feedback on thermal comfort. Post-completion performance testing included drone-assisted thermal imaging to assess building fabric performance and identify any heat loss issues.

Dundashill Platform 3. Image credit:Collective Architecture/ Keith Hunter Photography

Architect’s view

Collective Architecture was appointed by WSHA through their consultant’s framework to develop proposals for Dundashill at Platform 3. The brief was to design the affordable housing to Passivhaus standard and to allow for additional low carbon technology provision. WSHA was ambitious and forward-thinking on the project, pushing all the boundaries.

Achieving the precision required for Passivhaus certification requires careful coordination and effort on site. However, the layout repetition and the use of offsite construction played a key role in ensuring the project was delivered on time and to a high standard. Beyond the successful delivery, it brings long term benefits.- reducing operational carbon and helping address fuel poverty through significantly lower energy bills. In the current climate of rising energy costs, lower energy bills offer direct financial relief to households, supporting more stable month-to-month budgeting.

Platform 3 demonstrates how housing can be affordable, adaptable, and climate-conscious without compromising on design or quality. It supports the ambitions of WSHA and Glasgow City Council to deliver future-proof homes for residents priced out of ownership but not eligible for social housing. This project redefines what mid-market rental housing can achieve, setting a new standard for sustainable urban living in Scotland.

Delivering the project to rigorous Passivhaus standards translates to indoor comfort year-round, minimal heating requirements, and significantly lower carbon emissions, while maintaining superior air quality for occupants. Hearing from the residents that they feel comfortable in their homes is really positive. The residents' health and wellbeing is the most important outcome.

Emily Ong, Passivhaus Designer, Collective Architecture

Costs

The construction cost for the 90-unit mid-market rent residential development was approximately £17.5 million, with a GIFA of roughly 7,605 m², giving a construction cost of around £2,235/m². If the total project cost of £21.6 million is factored in (including landscaping, consultancy, and planning fees), the figure works out as approximately £3,061/m².

Key team

Architect & Passivhaus Designer: Collective Architecture
Contractor: CCG Scotland
Structural engineer: G3 Consulting Engineers
M&E consultant: RSP Consulting Engineers
Passivhaus Certifier: WARM

Dundashill Passivhaus social housing completed. Image credit: Collective Architecture

Congratulations to the project team for delivering Scotland's largest residential project to date. It's fantastic to showcase exemplar projects like Dundashill Platform 3 ahead of the introduction of the Scottish Passivhaus Equivalent policy, demonstrating Passivhaus occupant comfort and satisfaction and an industry capable of delivering Passivhaus at scale.