Sustainability Standards
Topics: houses, refurbishment, retrofit, sustainability
Estimated reading time: 8 minutes
Author: Becky Wootton, Architect BArch (Hons) DipArch
ARB registration no. 085383F
Becky is an associate at Architecture for London and she also leads our construction teams. She has direct oversight of site progress, ensuring design quality and low-energy strategies are carried through to each completed home.
Contact me: 020 3951 9790
Introduction
Creating an energy-efficient and comfortable home is becoming increasingly important in addressing climate change and reducing our carbon footprint. Some of the key sustainability standards, including EnerPHit and Home Quality Mark (HQM), are explored in this article.
These standards can be useful targets to aim for in sustainable housing design and renovation. Whether you are retrofitting an older Victorian home or building a new house, these frameworks can help you make better informed decisions about energy savings, efficiency and the overall comfort of your home.
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A sustainable retrofit of a beach house in Dorset with a timber structure and wood fibre insulation
Residential Sustainability Standards
EnerPHit standard
The EnerPHit standard outlines requirements for retrofitting existing buildings to make them more sustainable and energy-efficient. The requirements are similar, but slightly less rigorous, when compared to full Passivhaus, as they accommodate the limitations of older buildings.
EnerPHit retrofits can reduce energy demand by 75–90%, helping homeowners cut heating and cooling costs, while improving thermal comfort.
A sustainable retrofit of an Edwardian house in Muswell Hill that aimed for EnerPHit standards
Enerphit vs Passivhaus – what’s the difference?
The Passivhaus standard is typically applied to new-build properties, where energy efficiency can be integrated from the start. In contrast, EnerPHit is tailored to existing homes and heritage buildings, offering more flexible benchmarks due to existing building constraints.
Upgrading older or listed buildings to meet EnerPHit standards can pose challenges, such as the need for planning permission—particularly when replacing windows or adding external insulation. To address this, EnerPHit promotes a whole-building approach, encouraging designers to consider materials, ventilation, and structure holistically to maintain both energy performance and architectural integrity.
EnerPHit’s whole-building approach supports designers in selecting appropriate materials and strategies that improve performance without compromising the building’s historic character.
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A proposed new build house in Muswell Hill that will aim for the Passivhaus standard
Components of the EnerPHit sustainability standard
EnerPHit uses 5 key principles:
- High-performance insulation: Upgrading or adding insulation to walls, roofs, and floors helps retain heat, reducing the need for excessive heating.
- Airtightness: Sealing gaps and cracks creates a tighter building envelope, minimising heat loss and maintaining a more stable indoor temperature.
- Mechanical ventilation with heat recovery (MVHR): These systems supply fresh air while recovering heat from outgoing air, ensuring good air quality without wasting energy.
- High-quality glazing: Installing triple-glazed windows improves thermal performance while preserving a home’s original aesthetic.
- Thermal bridge-free design: By eliminating thermal bridges—areas where heat escapes easily—energy efficiency is significantly improved.
Home quality mark (HQM)
While EnerPHit is focused on retrofitting existing homes, the Home Quality Mark (HQM) applies to newly built homes. It is part of the BREEAM family of sustainability standards, specifically tailored to residential properties.
HQM indicates that a home has a reduced environmental impact, supports health and wellbeing, and is less expensive to run. It extends the principles of BREEAM to assess the performance and sustainability of homes in the UK. Recognising that our homes greatly affect our health and quality of life, HQM ensures new homes meet high standards. Therefore, if you’re searching for a new property, look out for HQM certification.
Bow Georgian house: MVHR unit insulation with galvanised ductwork.
The HQM has many assessment categories – to provide a comprehensive view of the home’s quality. These categories are split into 3 main sections – our surroundings, my home and delivery:
Our Surroundings
This unit focuses on the home’s relationship with its current and future surroundings.
- Transport and movement: Measures access to public transport, walking and cycling routes, and local services.
- Outdoor space: Assesses recreational opportunities and identifies ecological risks.
- Safety and resilience: Evaluates how the home responds to climate risks such as flooding and overheating.
My home
My home focuses on the internal living spaces, occupant well-being and cost of living.
- Comfort: Assesses indoor air quality, noise levels, and thermal comfort.
- Energy: Evaluates energy performance, including carbon emissions and local air quality impact.
- Materials: Looks at responsible sourcing, lifecycle impacts, and how materials enhance durability.
- Space: Reviews how living space and storage are used, with attention to accessibility and sustainable habits like recycling.
- Water: Monitors water usage and systems that help reduce unnecessary consumption.
Delivery
Delivery evaluates the quality of the construction process and the home’s sustainability standard in practice.
- Quality assurance: Ensures procedures are in place to deliver high-quality construction and to close the gap between design and actual performance.
- Construction impacts: Reduces environmental and social impacts during construction.
- Customer experience: Evaluates how well the finished home meets the homeowner’s expectations and needs.
Choosing to purchase a HQM certified home offers assurance that the home has a reduced environmental impact, has been built with the intention of improving health and well-being, and is cheaper to run due to the insulation and efficient systems in place within the building.
A highly insulated loft conversion in a retrofit in Highbury, north London
Sustainability Standards: things you can do now
You don’t need to wait commit to a full EnerPHit retrofit or buy an HQM-certified home to benefit from sustainable improvements. Small changes to your current home can still make a difference:
Here are some simple, low-cost energy-saving tips:
- Switch off unused lights: make a habit of turning off lights when leaving a room
- Install LED lighting: LEDs consume up to 75% less energy and last longer than traditional bulbs
- Use smart thermostats: control heating more precisely—only heat rooms when needed
- Improve loft insulation: up to 25% of heat is lost through the roof—insulation can cut this dramatically
- Seal draughts: install draught excluders on doors and windows to retain heat
- Close curtains at night: curtains act as an extra layer of insulation in cold months
- Consider secondary glazing: for older homes, this can improve thermal performance without replacing historic windows
When combined, these small actions reduce energy bills, enhance comfort and contribute to lowering carbon emissions.
A Georgian listed building with wood fibre insulation being installed
Final thoughts
Whether you’re retrofitting your existing home or considering a new-build purchase, sustainability standards like EnerPHit and the Home Quality Mark provide valuable guidance. They promote better construction practices, healthier indoor environments, and homes that are future-proofed against the challenges of climate change.
With growing energy prices and climate targets on the horizon, homes that are energy-efficient, comfortable, and resilient are no longer a luxury—they are a necessity.
Discover Architecture for London’s project portfolio. If you are seeking architects to work toward a particular sustainability standard, please contact us.
Sustainability Standards FAQ
They can. While full certification is not always necessary or practical, the underlying principles of standards like Passivhaus, EnerPHit and LETI can significantly improve even modest residential projects. Architecture for London applies these principles proportionately, focusing on fabric-first improvements, robust detailing, and efficient, simple services.
Higher performance targets can increase upfront construction costs, especially where deep retrofit or very high levels of insulation and airtightness are required. However, Architecture for London aims to integrate sustainability from the outset so that it is cost-effective, focusing on fabric-first measures, robust detailing and simple, durable systems that reduce running costs and maintenance over the building’s life.
While it may be challenging for every existing home to reach full net zero, deep retrofit guided by frameworks like EnerPHit and LETI can dramatically reduce energy use and carbon emissions. Architecture for London has delivered and is developing projects that approach net-zero operational performance through a combination of fabric upgrades, airtightness, efficient services, and, where appropriate, on-site renewables.
Current UK Building Regulations generally represent a minimum legal standard rather than best practice for sustainability. Architecture for London typically designs to exceed Building Regulations, aiming for much lower energy demand and carbon emissions by using frameworks such as RIBA 2030 targets, LETI benchmarks and Passivhaus principles.