In the drive to build new homes to an exceptionally high standard, including energy efficiency, the spotlight has fallen on the off-site construction of modular homes. These buildings are constructed as much as possible in an off-site factory location, where a skilled workforce is permanently based, and quality can be controlled much more easily. The finished components are then shipped to the final build site for installation and assembly. Sweden, for example, is now building 45% of their new homes by this method and the UK is set to increase the percentage of homes it constructs by this modern method. While the quality of construction is higher, how can you assess the buildings performance in the real world as compared to the computer modelled figures? The answer for Step Places was to undertake some collaborative research with the University of Salford via the Energy House 2.0 Project. The University’s researchers undertook detailed measurements to assess the buildings actual performance.
The work the University of Salford undertook was in situ, over three weeks in the winter, when it could be guaranteed of a ten-degree Celsius temperature difference (∆T). This is necessary in some of the tests to obtain meaningful data. There were four main tests:
- Air Permeability Test – This checks the air leakiness of the property which has a major effect on the energy efficiency of the building. It does this by installing a blower door which pressurises and depressurises the sealed, as built, building and the data is collected on sensors and relayed to a laptop computer.
- Thermography – this used a high-quality thermographic camera which allowed any air leaks and thermal bridges to be identified.
- Whole House Heat Loss Test, or Coheating – This used a series of thermostatically controlled heaters, fans and data collection for internal temperature and conditions, external temperature, and energy consumption.
- U Value measurements of walls, floors, and ceilings – This used a standard rig which included heat flux sensors, surface temperature and air temperature sensors.
All this data was collected and eventually analysed to produce a report for Step Places. The property performed very well, exceeding current building regulations. The tests did reveal where some minor improvements could be made in terms of construction off site and the assembly process on site.
The work the University of Salford has undertaken for us at Wigan Pier has allowed us to validate our new design and highlight the areas to improve in an already very airtight shell for marginal improvements in key areas allowing us to use the data collated and be ready for when we roll out our next modular homes scheme in Rochdale later this year.
Gareth Smith, Director at Step Places
For more information on Step Places, please visit: www.step-places.com