Passivhaus Affiliate

Saffron Acres Certified

Leicester City Council made Passivhaus certification an essential requirement for all 68 homes on the Saffron Acres development before granting planning permission. It was a condition imposed by the council when it sold the land for £1 to Saffron Lane Neighbourhood Council.

The timber framed homes varied from semi-detached to terraced with a total TFA of approximately 4,500m2. The different orientations of the plots made this an even greater challenge because it meant that a variety of fabric specifications would have to be used for insulation.

Saffron Acres 

PHT Patron member, Encraft, modeled the most challenging plots and developed four different fabric specifications, ensuring certification was successfully achieved at the design stage for all dwellings. By only modeling the most challenging plots on the site, there was a significant reduction in fees as fewer PHPP calculations were produced.

Numerous site visits followed and ensured regular inspections of air-tightness testing, MVHR commissioning, correct specification & installation of insulation. The airtightness test final results improved significantly from the first to the last plot – after some remedial work number 1 achieved 0.6 ach-1 and number 68 achieved 0.22 ach-1 first time!


Passivhaus Performance

Thermal Energy demand (≤15kWh/m2.yr)

Ranges from 14-20

Thermal Energy load (≤10W/m2)

Ranges from 8-10

Primary E demand (≤120kWh/m2.yr)

Ranges from 82-98

n50 ACH@50pascals (≤0.6ach@50pascals)

Ranges from 0.22 – 0.6

Saffron Acres - Timber construction Saffron Acres - Airtight layer


The Royal Institute of Chartered Surveyors are beginning to recognize price differences between the new-build developments adopting Passivhaus and those that don’t, so it is no surprise that achieving certification is becoming increasingly desirable, amongst both developers and the growing number of individuals who are electing to self-build. 


Saffron Acres 

The project commenced construction in July 215. All 68 plots achieved Passivhaus certification by January 2017, making Saffron Acres the largest Passivhaus residential development in the UK. Congratulations to all that were involved.


Key Team

Project Owner/Client East Midlands Homes/Westleigh Partnership/ Saffron Lane Neighbourhood Council 

Developer Emh (East Midlands Homes) 

Architect Rg + p Ltd

Contractor Westleigh Homes

Consultants Encraft

Certifier Mead: Energy & Architectural Design Ltd


Further Information

Previous PHT story:  68 homes under construction at Saffron Lane aim for Passivhaus – 15 April 2015


30th January 2017

< Back To News