Agar Grove Phase 1C – one year post‑occupancy review

Phase 1C comprises 125 units and is the first phase to be fully electric, with space heating and domestic hot water provided via heat pumps connected to an ambient loop network. 

Measured energy consumption is very low, with an Energy Use Intensity (EUI) of 49 kWh/m²/yr, which aligns with the operational energy limit set within the Net Zero Carbon Buildings Standard Version 1. 

The EUI includes all the energy consumption associated with the building. It’s our understanding that this is the first multi-residential project which demonstrates this level of exemplary performance. 

The purpose of the UK Net Zero Carbon Buildings Standard is to set out requirements for net zero carbon-aligned buildings that could – if the rest of the UK building stock were to collectively implement compatible interventions – enable the UK built environment sector to not exceed its share of our national carbon and energy budgets. 

The measured energy performance also closely aligns with Passivhaus standard modelling, suggesting no measured performance gap between design expectations and operation. 

The ambient loop network has delivered reliable heating and hot water to residents, operating at a measured coefficient of performance (COP) of approximately 2.3. This is slightly below the anticipated COP of around 2.5; however, the advantages include the elimination of distribution losses typically associated with heat networks and the potential integration of comfort cooling in the future.  

High levels of winter thermal comfort have been observed. Monitoring across a sample of six dwellings recorded an average internal temperature of 22°C during the winter period. 

Measured space‑heating demand across the same sample varied considerably but on average was 22 kWh/m²/yr, excluding one outlier dwelling where internal temperatures were maintained above 25°C throughout the year.

Winter indoor air quality was also excellent, with CO₂ concentrations exceeding 1,000 ppm for only 3.5% of the monitored period and never exceeding 1,500 ppm. 

Relative humidity only exceeded 60% for 0.1% of the time, suggesting the internal conditions were healthy and comfortable, helping eliminate any risk of damp and mould. 

Resident engagement formed a key part of the post‑occupancy evaluation process. This included direct feedback and the provision of graphical home user guides and posters to support residents in understanding and optimising the operation of their homes. Some images from the quick start home user guide are shown below.

An occupant survey was sent out to the residents at the end of the first year of occupancy. When asked about the temperature in their home in winter, 100% of residents said that the temperature was “just right”. When asked about the overall conditions in winter, 70% were “very satisfied” and the remaining 30% being “satisfied”. 

The results were similar for the conditions in summer, with 86% saying the temperatures were “just right”, and when asked about the overall conditions, 70% were “very satisfied”, and the remaining 30% were “satisfied”.

When asked, "Do you feel that your home has affected your health by making you feel more or less healthy than the previous home?" 86% responded that they feel “more healthy”. 

During the POE, residents responded positively to their new home. A resident living with her daughter in temporary accommodation described the flat as “perfect for me!”. A woman with a baby described it as “nice and cosy”. And a social tenant on the ground floor said “I love it here, it’s a dream come true”.