DesignForlU: Comparison of certified versus operational performance of energy efficient technologies

Start Date


End Date


Funding Body

Sustainable Energy Authority of Ireland

Principal Investigators

Dr. Paul O’ Sullivan

Postdoctoral Researcher

Dr. Adam O’ Donovan

Research Area

Energy Management




In the Irish built environment sector, the variation in design specification and operational performance of building envelopes, inadequate commissioning of energy systems, and the lack of good quality knowledge surrounding occupant behaviour can all lead to a design vs. measured performance gap. To ensure better predictions of performance at the design stage of a project an “in-use” factor is used to correct for this underprediction and can be as high as 1.8 in some instances. Obtaining more accurate information about the value of an in-use factor is a key requirement in ensuring national energy targets are achieved in practice. This project uses high-resolution measurements coupled with mechanistic energy models, calibrated using training data, to identify the range of in-use factors for a number of established low energy technologies in the Irish Energy sector. Specifically, a multi-parameter sensitivity study using a combination of real energy monitoring and calibrated parametric modelling will identify the key root causes for each in-use factor. Understanding the significance that different operating conditions and characteristics have on the performance gap is essential to the development of any climate mitigation plan. The outcome of the project will be a set of in use factors that can be used by designers depending on the type of occupancy behaviour that is expected, the microclimate the system will operate within and its operating conditions. The in-use factors will allow for the additional risk associated with uncertainty in design stage decisions.