Denby Dale Passivhaus

First UK Passivhaus to be built with cavity wall construction and one of the first certified Passivhaus homes in the UK.

• Cavity wall construction
• 118m2 three-bed detached house
• £141K basic build costs
• Minimal heating – using 90% less energy for space heating than the UK average
• Multi-award-winning!
• Design and build project led by 21°
• Later followed by the Golcar Passivhaus project, which developed some of the cavity wall detailing further

PLAY

Future Passiv

A short film making the case for Passivhaus low energy building in the UK

Background

The Denby Dale Passivhaus in West Yorkshire has sought to provide a solution to the urgent need to drastically cut the CO₂ emissions from buildings in the UK and has tried to create a low-cost and easily replicable template for low energy Passivhaus construction, using techniques and materials familiar to British builders.

Built by 21°’s construction division – Green Building Company –  the project is the first certified Passivhaus in the UK to be built using cavity wall construction and has pioneered the combination of British vernacular construction methods with the German low energy Passivhaus design methodology. The original design details developed for the project can also be used as a template for the construction industry as to how to minimize  thermal bridging, improve energy efficiency and maximise the airtightness of projects built using cavity wall construction.

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Passivhaus & UK policy

Denby Dale Passivhaus 5 years on

Technical Data

Final certification figures

• Total floor area: 118m²
• Treated floor area: 104.4m²
• Heating requirement/ year: 15 kWh/m²/year
• Heat load: 10 W/m²
• Primary energy requirement: 87 kWh/m²/year
• Airtightness: 0.33 ach @ 50 Pa (to Passivhaus and Euronorm standard)

U values

• Exterior wall: 0.113W/m²K
• Roof: 0.096 W/m²K
• Ground floor: 0.104 W/m²K
• Windows/ average: 0.8 W/m²K

Costs

In association with BUILDING magazine we contributed a regular blog from Project Leader Bill Butcher as the build progressed, highlighting along the way the special challenges – and pitfalls – of Passivhaus construction in a UK context.

Breakdown of costs

• Week one – Early lessons
• Week two – Why we chose cavity wall
• Week three – Dr Wolfgang Feist
• Week four – Reducing thermal bridging
• Week five – Materials
• Week six – Thermal bypass
• Week seven – The walls
• Week eight – The wall openings
• Week nine – Floor junctions
• Week ten – The roof
• Week eleven – Making the roof airtight
• Week twelve – Windtightness and reducing thermal bypass
• Week thirteen – Windows & doors
• Week fourteen – Ventilation (MVHR)
• Week fifteen – MVHR ducting design
• Week sixteen – Spreading the word
• Week seventeen – Achieving airtightness
• Week eighteen – The first airtightness test results
• Week nineteen – Heating
• Week twenty –  Coming to an end
• Week twenty-one – Certification!

Living in the Denby Dale Passivhaus

The owners of the Denby Dale Passivhaus also write occasional blogs, which chronicle their experiences of living in one of the UK’s first Passivhaus homes. The blogs look at what it is like living with MVHR ventilation and ultra low gas bills and also hopes to answer such things as how to dry towels in a Passivhaus and whether you can open the windows etc.

• Living in a Passivhaus: Moving in!
• Living in a Passivhaus: Autumn
• Living in a Passivhaus: Lessons of the winter
• Living in a Passivhaus: Snow update!
• Living in a Passivhaus: Spring
• Living in a Passivhaus: Summer

Technical data

Denby Dale Passivhaus Technical summary

Denby Dale Passivhaus Factsheet

Denby Dale Passivhaus Monitoring and Performance report