This guide introduces the principles of Passivhaus for new-build homes and EnerPHit for retrofits of existing buildings. Whether you’re planning a new sustainable home from scratch or looking to radically upgrade your current one, understanding these gold-standard design approaches is a powerful first step.

What Is Passivhaus?

Passivhaus (or Passive House) is the world’s leading standard for energy-efficient building design. Developed in Germany in the early 1990s, it focuses on radically reducing energy demand—especially for heating and cooling—through a fabric-first approach.

Unlike conventional homes, a Passivhaus maintains stable indoor comfort using very little active heating or cooling. It does this through five core principles:

1. High levels of continuous insulation

2. Airtight construction

3. Triple-glazed, high-performance windows and doors

4. Thermal bridge-free detailing

5. Mechanical ventilation with heat recovery (MVHR)

The result? A home that uses up to 90% less energy for heating than a typical UK building—and delivers exceptional thermal comfort, healthy air quality and low running costs.

What Is EnerPHit?

EnerPHit is the retrofit version of Passivhaus—designed for upgrading existing buildings to near-Passivhaus performance levels, even when full compliance isn’t technically or economically feasible due to constraints like orientation, structure or heritage restrictions.

EnerPHit follows the same core principles as Passivhaus but allows more flexibility. The goal is still deep energy reduction, increased comfort, and long-term sustainability, all while respecting the character and fabric of older homes.

At Material Works, we’re experienced in applying EnerPHit standards to varying types of home, and we know how to balance technical excellence with architectural sensitivity.

Why Build or Retrofit to Passivhaus or EnerPHit?

1. Sustainability First

Passivhaus buildings dramatically reduce operational carbon emissions through low energy use. Combined with natural materials, timber construction, and low-embodied carbon strategies, they are among the most climate-resilient housing solutions available today.

2. Healthier Homes

With constant fresh air delivered by MVHR systems, Passivhaus and EnerPHit homes offer exceptional indoor air quality—reducing allergens, humidity and pollutants. They also eliminate cold spots, drafts, and overheating.

3. Low Running Costs

Because the energy demand is so low, heating bills are significantly reduced. In many cases, a Passivhaus can be heated with the energy equivalent of a hair dryer. This provides long-term affordability and resilience to future energy price volatility.

4. Comfort All Year Round

Temperature stability, quiet interiors, and even light distribution make for a calm and enjoyable living environment. Passivhaus homes are designed with people at the centre—something we strongly believe in at Material Works.

5. Quality and Longevity

Passivhaus certification requires rigorous design and testing, ensuring long-term building performance. Every detail matters—and that suits our philosophy of clear, thoughtful, high-quality contemporary architecture.

The Design and Delivery Process

Whether new-build or retrofit, Passivhaus and EnerPHit require a holistic and coordinated design approach. As certified Passivhaus designers, Material Works brings deep understanding and rigorous detail to every stage of the process:

1. Early-Stage Planning

Success starts with an integrated strategy. We assess orientation, shading, form factor, and construction type early on, ensuring the fundamentals of Passivhaus can be built into the design from day one.

For retrofits, we analyse the existing building fabric, thermal bridges, airtightness potential, and upgrade sequencing to create a clear EnerPHit roadmap.

2. Fabric-First Design

Passivhaus focuses on reducing energy demand through the building envelope. We specify:

• Continuous insulation, often using natural materials like wood fibre or cellulose

• High-performance glazing, optimised for solar gain and shading

• Airtight layers and tape detailing to reduce air leakage

• Thermal bridge-free connections in junctions and penetrations

We integrate these seamlessly with elegant, contemporary architecture tailored to your life.

3. MVHR Integration

A carefully designed mechanical ventilation with heat recovery (MVHR) system ensures continuous fresh air, moisture balance, and heat recovery efficiency of up to 90%.

At Material Works, we design these systems not just for function, but to work discreetly and beautifully with the architecture.

4. Design Modelling & Certification

We use the Passivhaus Planning Package (PHPP)—a robust energy modelling tool—to verify performance at each stage. We coordinate with certified assessors and trades to ensure construction aligns with the design intent, and that every detail contributes to certification success.

Retrofitting with Sensitivity and Impact

Retrofitting to EnerPHit isn’t just about insulation and windows. It’s about transforming the performance of your home while preserving its character. Our approach respects the spirit of older buildings, incorporating:

• Breathable natural materials to preserve fabric health

• Discrete insulation solutions for period features

• Sensitive façade upgrades in conservation contexts

We understand heritage planning, construction sequencing, and retrofit phasing—making us the right partner for long-term, sustainable upgrades.

Why Choose Material Works?

We are certified Passivhaus designers, but more than that, we are architects who value clarity, craftsmanship, and care. Our work brings together:

• Sustainable design thinking rooted in real performance

• Healthy, natural materials that support wellbeing

• Clean, contemporary architecture with integrity

• Detail-focused project delivery that leads to lasting results

Whether you’re planning a new Passivhaus or retrofitting your existing home to EnerPHit standards, Material Works brings the expertise, creativity and commitment to help you build a home that’s future-ready—today.

Ready to Take the Next Step?

If you’re considering building to Passivhaus or retrofitting to EnerPHit, get in touch. We’ll help you understand the process, assess the feasibility for your home or site, and guide you towards a healthier, smarter, and more sustainable way of living.