Balancing energy-efficiency and health in retrofitted dwellings to the EnerPHit standard: achieving optimal indoor environmental quality

It is widely known that the UK has the least energy-efficient building stock in Europe, which contributes to over 30% of total greenhouse gas emissions. To improve the energy performance of both new and existing buildings, the UK is implementing policies to improve performance. One of the retrofit solutions, EnerPHit, has been applied in a tradiational stone tenement building in Glasgow as a test of this approach.
The findings to date indicated that the project has been effective in providing comfortable, healthy dwellings with low energy usage and high levels of occupant satisfaction. but some individual dwellings are exceeding targeted consumption levels. Despite this, the dwellings maintain good indoor temperatures, generally within the EnerPHit performance targets, without sacrificing thermal comfort. The indoor air quality and ventilation targets were met with CO2 levels below 1,000ppm throughout the monitoring period, and there was no evidence to suggest that the MVHR systems were switched off or malfunctioning. Currently, there are no apparent concerns regarding interstitial moisture in the construction.
There are valuable lessons to be learned from this retrofit program, particularly the significance of occupant behaviour, expectations, and their engagement with building systems, but the project has also highlighted the need for construction skills to enable delivery and proper maintenance and operation of new building systems.