Accessible Manchester retrofit delivers comfort and low bills

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Development type: Deep retrofit of 1980s bungalow.
Method: Fabric-first approach with external wall insulation, timber frame extensions, and mechanical ventilation with heat recovery (MVHR)
Location: Suburban Manchester
Standard: CarbonLite Retrofit certified
Space heating cost: £42/month
(total energy bills – see In detail panel for more)

When homeowner Steve discovered a neglected 1980s bungalow during the pandemic, he faced a dilemma.

Born with significant physical differences, the computer programmer and Team GB Paralympian needed a home that would work for him long-term while addressing the rising energy costs that plagued his previous flat.

What emerged from this personal challenge would become the 2025 Exemplar Sustainable Buildings Awards winner for retrofit projects—a transformation that proves accessibility and sustainability can be mutually-reinforcing design principles.

Working with Hannah Dixon at Manchester practice Progress in Practice, the Ward Grove project is achieving exceptionally low metered energy use while delivering comprehensive accessibility features. The calculated energy use intensity – which in this all-electric house means the energy imported from the grid, as measured at the meter – is just 38 kWh/m²/yr.

The result is a home where Steve pays just £42 monthly for energy bills and declares simply: "It is a fantastic house."

The project's success lies not in choosing between accessibility and environmental performance, but in recognising how thoughtful design can deliver both. Every decision — from the internal garage access that keeps Steve dry when transferring from his car, to a heating system design that eliminates obstacles in the form of radiators — demonstrates how user-centred design can naturally align with sustainable building principles.

Universal design as environmental strategy

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The accessibility requirements that initially seemed like design constraints became catalysts for innovative solutions. Steve's need for an internally connected garage, allowing weather-protected access to his vehicle, required careful integration with the building's thermal envelope. Rather than compromise the insulation strategy, the design team used this as an opportunity to demonstrate how accessibility features could enhance rather than undermine performance.

"The main area accessibility had an impact on was the garage," says Hannah Dixon, architect and director of Progress in Practice.

The integration required sophisticated detailing to maintain the continuous insulation layer whilst providing the step-free access Steve required. The solution involved new timber frame construction with wood fibre insulation, ensuring no thermal bridging whilst creating the spatial flow needed for wheelchair accessibility. Interior accessibility features were crucial. Pocket doors sliding into walls eliminate the swing space of traditional doors, creating more efficient room layouts whilst requiring no effort to operate.

Steve's lowered kitchen worktops — 80 cm rather than the standard 90 cm — reduce material use whilst providing the ergonomic access he needs, while a stepped approach to his bath eliminated a ‘high jump’ entry that he wanted to avoid.

The underfloor heating distribution proved particularly effective for accessibility. Unlike traditional radiators that can obstruct movement and create uncomfortable hot spots, the even temperature distribution provides consistent comfort throughout the space, delivered through a screed finished with a Granorte cork floor.

Integrated thinking

The underfloor heating proved particularly effective for accessibility by eliminating the obstacles of radiators.

The transformation of this 1980s bungalow into a certified CarbonLite Retrofit demonstrates how ambitious performance targets can be achieved within existing building constraints.

The original property, unoccupied for several years with "dated finishes, direct electric heating system, and all of the usual terrible glazing," presented the typical challenges of its era whilst requiring comprehensive accessibility modifications.

Dixon's team approached the retrofit with a fabric-first strategy, applying external wall insulation to the existing brick cavity walls whilst constructing new elements in timber frame with wood fibre insulation.

This was part of a conscious choice to use natural materials – including cellulose insulation, cork flooring, and healthy interior finishes.

"We try to use natural materials," Dixon says, noting that fire regulations provided the primary constraints rather than thermal performance requirements. Efforts to reduce embodied carbon also informed the spec, including the glulam beams. “This was initially specified by structural engineer as steel, but changed to glulam for embodied carbon reasons,” says Dixon. “It also looks lovely. The builder initially suggested switching back as a cost saving, but actually the glulam turned out to be cost neutral.”

A pragmatic approach to integrating non-standard low carbon materials was necessary, Dixon explains, for a simple reason. “We had to balance this with trying to design the details in a way that is reasonably familiar to most builders, as we didn’t know at the time who was going to build it,” she says. The project's innovative approach initially faced scrutiny during the planning process, requiring specialist intervention to justify the design rationale. Planning consultant Emma Jones of Acer Town Planning was brought in after some early pushback from the local authority during pre-application discussions.

• Front of house before Front of house before
• Interior kitchen before Interior kitchen before
• New slab throughout. Insulation is to go above, followed by underfloor heating within a wet screed and cork flooring – delivering a comfortable, warm surface for a client who will spend more time closer to the ground New slab throughout. Insulation is to go above, followed by underfloor heating within a wet screed and cork flooring – delivering a comfortable, warm surface for a client who will spend more time closer to the ground
• Primary glulam structure going in – which ended up being cost neutral compared to the steel beam proposed by the structural engineer Primary glulam structure going in – which ended up being cost neutral compared to the steel beam proposed by the structural engineer
• Timber frame in progress, with studs sitting on Marmox blocks, prior to the insulation layer going in Timber frame in progress, with studs sitting on Marmox blocks, prior to the insulation layer going in
• View into house from front, where integrated garage is going in – a core part of the brief for a client coming in and out of the car with a wheelchair in the Manchester weather View into house from front, where integrated garage is going in – a core part of the brief for a client coming in and out of the car with a wheelchair in the Manchester weather
• Wood fibre insulation to roof Wood fibre insulation to roof
• The inner layer of the two layer external insulation, with battens between the EPS for fixings for timber cladding. The outer layer, yet to be added in this photo, is continuous EPS. Mineral wool at the head of the wall joins the EPS to the cellulose insulation in the loft. XPS insulation is taken as far as possible below DPC. The inner layer of the two layer external insulation, with battens between the EPS for fixings for timber cladding. The outer layer, yet to be added in this photo, is continuous EPS. Mineral wool at the head of the wall joins the EPS to the cellulose insulation in the loft. XPS insulation is taken as far as possible below DPC.
• Viking triple glazing and high performance doors. EPS insulation wraps around reveal to meet frame. Window on left insulation in progress. Door on right insulation fitted Viking triple glazing and high performance doors. EPS insulation wraps around reveal to meet frame. Window on left insulation in progress. Door on right insulation fitted
• Insulated house with triple glazing (to the right), uninsulated garage (to the left) Insulated house with triple glazing (to the right), uninsulated garage (to the left)
• PIR insulation below screed with 25mm upstand throughout, fitted snuggly with no gaps. It was insisted that Kingspan and Celotex were not specified due to connections with the Grenfell atrocity PIR insulation below screed with 25mm upstand throughout, fitted snuggly with no gaps. It was insisted that Kingspan and Celotex were not specified due to connections with the Grenfell atrocity
• A tricky junction necessitated running MVHR ductwork through the airtight layer into the loft (within the thick insulation layer) and back into the living space A tricky junction necessitated running MVHR ductwork through the airtight layer into the loft (within the thick insulation layer) and back into the living space
• Airtightness complete – with the builder so keen to do well on airtightness that he went beyond the original detail by wrapping the internal partition, which was then taped onto the glulams and DPM Airtightness complete – with the builder so keen to do well on airtightness that he went beyond the original detail by wrapping the internal partition, which was then taped onto the glulams and DPM
• Airtightness, showing living space wrapped like a Christmas present, Installed by a female tiler, who was new to retrofit, but excelled at airtightness Airtightness, showing living space wrapped like a Christmas present, Installed by a female tiler, who was new to retrofit, but excelled at airtightness
• Cellulose in loft, used around the repeating trusses – partly for its low embodied carbon and partly because it made it simple/possible to fill all of the little gaps between a lot of complicated structure. Cellulose in loft, used around the repeating trusses – partly for its low embodied carbon and partly because it made it simple/possible to fill all of the little gaps between a lot of complicated structure.
•  

"Hannah of Progress in Practice brought me in because they had initially had some pushback from the local authority," Jones explained. The planning challenges centred on how accessibility needs informed design decisions that departed from standard approaches.

Traditional space standards for external areas, for instance, didn't account for Steve's specific requirements to maximise internal accessibility.

"The council has certain space standards for external space, but in this case, because the client had specific needs, it was designed to maximise the internal space," Jones says, noting how she justified the smaller garden by emphasising the innovative fusing of the passive house-informed CarbonLite Retrofit standard with accessibility integration.

The experience highlighted how planning frameworks struggle to accommodate projects that challenge conventional standards, even when delivering superior outcomes.

Balancing ventilation and client needs

The house also eschewed convention in its approach to ventilation, even in the context of the kinds of low energy buildings featured in this magazine. This may not be obvious to the casual reader, as the house features a whole house mechanical ventilation with heat recovery (MVHR) system. However, it is common in low energy buildings to supplement the MVHR with fenestration strategies that facilitate cross ventilation or stack ventilation – most notably to purge ventilate to reduce temperatures during summer nights.

At Ward Grove, the bungalow format itself created challenges for natural ventilation due to security concerns—"I can't leave my windows open at night", says Steve. The MVHR was therefore crucial to ensure consistent air quality and thermal comfort – two aspects which natural ventilation alone cannot reliably deliver.

While natural ventilation is inherently inconsistent and arbitrary, ranging from little or no air to the sort of occasional gale force breezes that cause many users to block vents, the house is provided with a constant, predictable supply of filtered fresh air - and at comfortable temperatures.

The MVHR system brings in fresh air, filters out pollutants before it reaches the home, and simultaneously exhausts stale, moist air — but not before grabbing hold of about 90 per cent of the heat that would otherwise escape, and transferring it to the incoming air. But accommodating a centralised ventilation system within a relatively constrained space without compromising the building envelope proved challenging.

The design solution involved a relatively complicated junction taking the MVHR ductwork from the utility up through the airtight layer into the loft – but under the thick insulation layer – and back through the airtight layer into the living space.

“A lot of thought and effort was put into the airtightness around these penetrations,” says Dixon, “given the access into the loft space was also challenging. This was not an ideal detail, but we were very constrained by space as the bedroom areas already have a low head height.”

It was worth the effort, with the MVHR really proving its worth in winter. Principally, this is because it significantly reduced the home’s exposure to polluted outdoor air. Air pollution often increases in winter due to colder, drier air and increased domestic fuel burning – with Manchester air quality spiking last winter at a score of 110 AQI on Plume’s air quality index.

Plume describes levels of 100 and above as very high pollution, noting that “Everyone may start to experience more serious health effects at these levels”. But last winter, the MVHR served another unexpected function.

It proved particularly valuable during the heat pump breakdown that occurred during cold weather — added to the building’s highly insulated, highly airtight nature, the heat recovery ensured the system failure went unnoticed initially, demonstrating the resilience built into the house.

Steve reports "very steady" humidity levels throughout the year, demonstrating how accessibility needs drove the selection of systems that enhance both comfort and performance.

Melissa Edge, MVHR design manager at 21 Degrees, who designed the ventilation system for the project, explains the fundamental shift required in high-performance dwellings: “In the past, people didn't have to consider ventilation; it was just part of our leaky buildings, but as we are now taking airtightness seriously and having proper insulation, you need ventilation. The only way to do it is mechanically.”

However, Edge notes that 21 Degrees' role was limited to system design: “If we don't do the supply, we can't guarantee that the parts we specified have been fit and delivered. It's not the norm for us,” she says.

This design-only approach, while ensuring specialist expertise in system specification, places responsibility for installation quality on the main contractor. The distinction between design and installation becomes crucial when considering system performance.

Many homeowners worry about noise from mechanical ventilation, but as Edge points out, this may be because people’s perceptions have been shaped by undersized extract fans that abound in typical new homes. “We design the systems to be inaudible. We guarantee that,” she says. “You might think of an intermittent fan. This is continuous ventilation,” Beyond air quality, the MVHR system contributes directly to the project's energy performance.

Edge explains how proper ventilation design supports the overall building strategy: “When it is designed well and installed properly, it is excellent. It also aids in heating, bringing the requirement down slightly.” This connects well to Steve's experience with the underfloor heating system and overall energy performance.

Self-generated electricity to compliment electrified heat

A 5kW rooftop solar array with battery storage provides renewable electricity to power the heat pump and run the house. The net effect? Steve's actual electricity consumption costs just £512 annually – an average of just over £42 per month. The combination of high-performance fabric, a heat pump running at low temperatures and a PV array and battery which either serves the house or sells surplus electricity into the grid means that at times he finds himself 'massively in credit' with his energy supplier.

In the summer months, his solar generation covers virtually all his electricity needs, meaning he is essentially only paying standing charges while his credit balance continues to grow. “The panels are on a bungalow, meaning I get comparatively much worse solar in winter,” says Steve, “not just because of the gloom and shorter daylight, but because of buildings blocking the low sun. Friends round the corner still produce a fair bit in winter, as they often remind me. But they have to use stairs, so I suppose it evens out.”

Future directions

The Ward Grove project's recognition at the Exemplar Sustainable Buildings Awards — competing against established practices including Architype and John Gilbert Architects — signals growing industry appreciation for integrated design approaches.

The project challenges the conventional separation of accessibility and sustainability consultancy, demonstrating how user-centred design can drive environmental innovation rather than constrain it. Steve's journey from uncertainty — "I didn't really know what I was doing" — to confident building operation and planned improvements illustrates the potential for client empowerment in high-performance building delivery. His background developing environmental video games 15 years earlier, examining scenarios for two degrees of warming, provided climate awareness that aligned with Hannah Dixon's sustainability philosophy.

"When you see the light" of proper sustainable construction, Dixon explains, "it's very hard to go back and do things that are worse."

The skills required for passive house construction, she argues, "aren't that hard; it's really about keeping it to a certain level and doing it properly." The challenge lies in industry culture, time pressures, and the individualised working patterns that undermine quality delivery.

For Steve, the building's summer performance represents an ongoing design challenge that mirrors broader climate adaptation needs. While "amazing in winter," the building requires active management during heatwaves, though Steve notes his comfort levels matched or exceeded those of friends in Victorian houses during extreme temperatures. His planned external blinds and smart home integration demonstrate how high-performance buildings can evolve with occupant understanding and changing climate conditions. The economic implications extend beyond individual project success.

“There is huge economic potential, both in new build and from a retrofit point of view, that could benefit the wider economy,” Dixon says. The building's transformation has resulted in energy abundance.

In real terms this means substantial credit accumulation as the solar array generates surplus power, demonstrating the financial sense of taking integrated approaches. Ward Grove's success challenges the retrofit industry to reconsider the relationship between accessibility and sustainability. Rather than treating universal design as a constraint on environmental performance, the project demonstrates how user-centred thinking can drive innovative solutions that deliver both social and environmental benefits.

As Steve concludes, the bottom line is simple: "It is a fantastic house." For an industry seeking to scale sustainable retrofit whilst addressing diverse housing needs, Ward Grove provides a compelling template for integrated excellence.

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