The Sigma Home was the first home in the UK designed to Level 5 of the Code for Sustainable Homes.

Comprising two units, one complete and one left unfinished to demonstrate the innovations, the Sigma Home benefits from modern methods of construction with closed-panel timber frame construction at its heart.

It was occupancy tested by a local family who lived in it for two weeks each season over the course of a year. Findings from the project were used to evolve future home designs from the Stewart Milne Group.

In 2011, Rexel Energy Solutions and the Stewart Milne Group formed a partnership to refurbish the Sigma Home. Rexel have refitted it to showcase and test the most innovative low energy products and technologies.

This is an evolving project which will be constantly updated to incorporate the latest advances in the marketplace.


Built buy Stewart Milne Group in 2007 on a modular foundation system using pre-cast piles and beams, the construction consists of highly insulated closed panel timber frame walls; three different pre-fabricated timber floor cassettes; and pre-insulated roof cassettes. Bathroom pods are also pre-fabricated.


Materials & Technologies

  • High levels of insulation – provided by wall, floor and roof elements coupled with high-performance timber windows
  • Renewable energy – heating and hot water provided by solar thermal and photovoltaic roof panels and wind turbine
  • Electric car charging point
  • Phase change wall board to regulate indoor temperature.



Airtightness testing and U-value testing

Air Tightness Result
1.00 m3/(h.m2) at 50Pa
element value. U value W/m2K
Walls 0.15
Glazing 0.68 triple windows
roof 0.15
floor 0.18

Building controls by Siemens and Honeywell

– Heat recovery by Vent Axia

– Solar thermal by Ideal

– Solar PV

– Smart metering by Rexel

– SCR antimicrobial wall and ceiling coatings

– Voltage optimisation by Marshall Tufflex

– Air source heat pump by Dimplex

– Electric vehicle charging points by Schneider and Siemens



Lead Contractor: Stewart Milne