At Progress in Practice, we offer a comprehensive range of architectural and sustainability services tailored to low-energy, Passivhaus, and retrofit projects. Our services span the full project journey — from initial concept and feasibility, through design development and technical detailing, right up to contract administration and aftercare. We specialise in PHPP (Passivhaus Planning Package) modelling to accurately assess energy use and embodied carbon, helping you make informed choices that support both comfort and sustainability.

We work on a wide variety of projects including new build Passivhaus homes, deep whole-house retrofits, community schemes and masterplanning. Our approach is highly collaborative: we engage closely with clients throughout the design process and can also help connect you with specialist contractors and consultants when needed. We aim to deliver buildings that are low energy, healthy, beautiful and built to last.

Retrofit is a broad term generally used to describe the upgrading of existing buildings. Within the architectural community it can cover a wide range of approaches. At Progress in Practice, we use the term to mean the reduction of a building’s energy demand through carefully considered energy-saving measures such as improved insulation, airtightness, high-performance glazing and effective ventilation.

We always take a whole-building approach. This means retrofits are properly planned and coordinated, helping us avoid building in risk, while making the most of every opportunity to improve performance.

We apply the principles of Passivhaus design to all buildings—large or small, new or existing—whether or not they are aiming for formal Passivhaus certification. This is because Passivhaus design is rooted in building physics, which helps ensure quality, reduce risk and minimise (or eliminate) the performance gap.

The Passivhaus Standard is the world’s most rigorous building standard, using building physics to minimise a building’s energy demand.

Beyond its environmental benefits, Passivhaus offers many practical advantages. Chief among these is comfort: draught-free spaces, stable internal temperatures and consistently warm surfaces. By eliminating cold spots and damp, and by incorporating mechanical ventilation with heat recovery (MVHR), Passivhaus buildings also deliver excellent indoor air quality and a very healthy living environment.

To achieve Passivhaus, a project typically involves:

1. Designing the building carefully from the outset, with a relatively simple form, balanced glazing and minimal complexity.

2. Modelling the design in PHPP (the Passivhaus Planning Package) to confirm the specification needed to meet the space-heating target (15 kWh/m².a for new buildings).

3. Specifying high levels of continuous insulation, high-quality triple glazing, exceptional airtightness and MVHR.

4. Developing a detailed design that enables these standards to be achieved on site.

5. Demonstrating quality during construction through records such as photographs, delivery notes and invoices.

6. Appointing an independent Passivhaus Certifier to verify both the design and construction.

For more information, visit:

• Passivhaus Trust - https://www.passivhaustrust.org.uk/

• Passivhaus Institute - https://passivehouse.com/en/home/

EnerPHit is the Passivhaus standard for retrofits. It follows the same core principles as Passivhaus, but allows for a higher space-heating demand—25 kWh/m².a—to make the standard more achievable for existing buildings.

When discussing low-energy buildings, it’s important to be clear about terminology. Passivhaus Standard has a very specific meaning: 15 kWh/m².a for new buildings, and 25 kWh/m².a for retrofits (EnerPHit).

The term passive is often used more loosely, sometimes by people who don’t fully understand the standard. This can lead to the assumption that a building performs close to Passivhaus levels, when in reality it may fall well short.

Without PHPP modelling, robust quality assurance and independent certification, it is extremely difficult—even for experts—to predict how a building will actually perform. The Passivhaus process is what delivers reliable outcomes, high construction quality and a dramatically reduced performance gap, which in the UK is estimated to range from 50% to 200%.

Yes. The AECB CarbonLite standards for new builds and retrofits use the same core principles as Passivhaus, including PHPP, but with slightly less demanding targets. These can be particularly useful for existing buildings where constraints of form or construction make Passivhaus or EnerPHit unachievable.

While there are many other standards available—some of which offer value in specific areas—none match the robustness of the Passivhaus approach. Passivhaus allows you to predict and rely on building performance in a way no other UK standard currently can.

Visit - https://aecb.net/

Low-energy buildings combine high levels of insulation and airtightness with excellent detailing, high-quality components (such as windows), and a whole-building ventilation strategy. Simple!

Building to Passivhaus standard typically adds around 10% to the cost of construction compared to a high-quality, best-practice new build. This premium is usually offset over time through energy savings, alongside significant gains in comfort and health.

Passivhaus does not prescribe a specific construction system, but it does require the elimination of thermal bridges and excellent airtightness. With good detailing, most construction methods can be made Passivhaus-compatible.

We often use prefabricated timber frame systems, as they are low-carbon and well suited to achieving high levels of detailing—though it’s worth noting that not all timber frames are created equal. Recently completed Passivhaus projects using this approach, and delivered to a high standard of finish, have typically cost around £3,000–£3,500 per square metre. For a 150 m², four-bedroom home, this equates to an approximate build cost of £450k–£525k.

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This is a great question—and one that’s very difficult to answer precisely.

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As a starting point, we typically use £2,000 per square metre for a deep, whole-building retrofit. Costs will increase if remodelling or extensions are included. A compact three-bedroom terraced house might start from around £150k for a full retrofit, but existing buildings vary enormously, particularly in terms of condition.

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Most of our retrofit projects are £200k+, which we find is often the sweet spot for delivering real value. We can also offer standalone Retrofit Assessments or ad-hoc consultancy where full architectural services aren’t required.

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For smaller projects we often refer people to our lovely colleagues at People Powered Retrofit (https://retrofit.coop/) here in Greater Manchester, or the National Retrofit Hub for further afield.

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This is an age-old challenge. Choosing the wrong builder can have serious consequences, so it’s important to take your time and feel confident in your decision.

At Progress in Practice, we work closely with a small number of specialist builders who we trust to deliver high-quality, low-energy projects. We’re always happy to make introductions or help manage a tender process. Where these builders aren’t suitable—due to location, availability or project type—we can help you identify and assess alternatives.

Recommendations from trusted sources are a great starting point, but remember that low-energy projects demand higher standards. Open conversations with prospective builders about complex details and construction approaches can be very revealing.

Some red flags to watch out for:

• Being too relaxed about low-energy or Passivhaus construction.

• Lack of transparency around pricing.

• Reluctance to work collaboratively with an architect.

• Patronising or dismissive about your (sometime unusual) energy-saving requests

Above all, trust your instincts. If something doesn’t feel right early on, it’s unlikely to improve over a long project. We strongly recommend visiting previous projects and speaking with past clients. Basic checks on Companies House are also advisable.

If you’re unsure, talk to us—we’re always happy to offer honest, impartial advice.

Our fees are bespoke and tailored to each project, covering a wide range of services including architectural design, Passivhaus consultancy, and retrofit coordination. The cost depends on the level of support you need as well as the size and complexity of your project. We recommend starting with an initial consultation, which is free of charge, so we can understand your requirements and provide a clear, personalised proposal.

In our experience, our fees are broadly in line with other firms of a similar size. However, by offering fully integrated Passivhaus expertise alongside architectural services, we’re able to provide exceptional value and ensure your project performs as intended.

Not at all. You can appoint us for a single stage to start with and see how the process feels. If at any point you decide not to continue, there’s no obligation to do so.