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Case studies

Here are some examples of the projects carried out at the Energy House.

The Green Deal Trial Monitoring Project being carried out on behalf of the Department for Energy and Climate Change (DECC) is investigating the impact of sustainable retrofits on the performance of homes and outcomes for occupants.  We are partnering with the Greater Manchester Low Carbon Hub which works with 10 local authorities and social housing providers in the region.


The Green Deal Trial Monitoring Project breaks from the practice of using models, such as RdSAP, by investigating actual performance of improved homes, the impact on occupants, and some of the associated risks of sustainable retrofit.

What we are doing:

  • Monitoring internal conditions and rate of energy use, using wireless sensors  
  • Conducting a series of interviews with occupants to assess comfort levels  
  • Measuring the rate of heat flow through the walls (U value testing)  
  • Using infrared images to assess the performance of the whole building and identifying patterns of heat loss  


The study is ongoing, the initial findings are:

  • Sustainable retrofit to one part of the sample triggered a 50% improvement in performance  
  • A post-retrofit study of occupants highlighted a considerable improvement in their newly-improved properties.

Green deal trial monitoring projectDECC logo

Combisave is a device that fits onto a combination boiler and saves water and gas during the heating of domestic hot water.

After conducting a series of field tests the company approached the Energy House team to carry out a flow test on the unit under controlled internal and external conditions.


  • Study flow rates and temperature of the hot water outlet in the kitchen  
  • Test a prototype device  
  • Film an instructional video of how to install the unit.  

What we did

  • The environmental chamber was held at 5°C  
  • The Viessmann combination boiler in the Energy House was fitted with a Combisave device  
  • The house temperatures were set to 21°C in the main living area and 18°C in other areas  
  • Flow and temperature was recorded from the hot water outlets.  


Combisave used the data to ratify the design of the unit and successfully launch it onto the market, achieving sales of 30,000 units in the first year of trading.

“Developing a new innovation, bringing it to market and bringing it to people’s attention is very difficult but it would have been a whole lot harder without the support of the Energy Hub team at the University of Salford.”

Combisave 2014

Combisave imageCombisave logoEDF logo

Saint Gobain logo

Over a period of three months Saint-Gobain worked closely with Salford University, Leeds Beckett University and Saint-Gobain Recherche on what is believed to be the most in-depth study into whole house retrofit.

What attracted Saint-Gobain to the Energy House was the opportunity to work in a facility where climatic conditions could be maintained, varied and repeated and the results accurately monitored, providing the confidence that the results were due to our interventions with no extraneous factors obscuring  performance.


The objective of this phase of testing was to carry out a full retrofit of the building, but in a way that allowed stage by stage savings to be visible, in terms of performance changes in whole house heat loss and air permeability. This was carried out under closely controlled and observed conditions.

What we did

External wall insulation to gableThe approach to the project was based on a multi-comfort and fabric-first approach, key components of Saint-Gobain’s strategy. Multi-comfort  is about careful teamwork, preparation, detailing and workmanship to achieve best practice and a significantly more comfortable and healthy internal living space for occupants.

A fabric-first approach determines that performance of the building fabric should be addressed before improvements to heating and renewables are considered. However, it was also necessary to understand the performance that can be achieved from a conventional whole-house retrofit – this was not  about trying to achieve utopian performance levels.

Standard systems were installed and designed to achieve insulation levels required by Building Regulations. Areas that are often seen as difficult to insulate, such as loft eaves and external window reveals, were left untreated as might commonly occur in typical refurbishments providing data to understand  the dynamics of thermal performance and airtightness at these junctions in controlled conditions.

Removal of existing floor in preparation for under floor insulationrear elevation with external wall insulation

The project team, led by Simon Gibson, R&D Manage, Saint-Gobain UK spent three months at the Energy House and the close collaboration between Leeds Metropolitan University, Salford University and Saint-Gobain Recherche resulted in measurements being taken by 414 sensors to compare pre- and post-installation  energy performance, air leakage and comfort.

Floor insulation installationThe ‘baseline’ was set at a level representative of the majority of UK housing. Instead of starting with the single-glazed windows  of the Energy House, typical 1990’s double-glazing was installed – reflective of windows found in many properties that would benefit from improved glazing unit upgrades. The old loft insulation was retained and topped up to today’s standards. Finally, in order to test multiple solid  wall insulation measures and to reflect the hybrid approach internal wall insulation was installed on the front elevation and external wall insulation on the side and rear elevations.


data was logged continually for the period of the trialSaint-Gobain and the project team were delighted to find that the heating demand of the property was reduced by 63%.  Using typical gas costs this represented a saving of almost £350 per year and indicated that a small dwelling could be heated for less than £4 per week. A significant saving of 1.45 tonnes of CO2 per year was also indicated.

It was also notable that a 50% reduction in air-leakage resulted from the interventions and this in combination with the thermal improvements resulted in a more comfortable internal environment where more of the house could be used with no impact on energy costs, showing the value of a whole-house,  holistic approach to retrofit.