Hook Hollow – One year on.

June, 2025 |

We have been reviewing the PH15 built project at Hook Hollow, especially with the clients, White Horse Housing Association (WHHA). This was a first experience of WHHA delivering a Passivhaus affordable scheme and has been very positive for them, even with the tweaks and niggles that arise, especially in the first year after occupation. Here is a distilled top five learning points –

1. WHHA felt very supported as did the architects, by the contractor training element integrated into PH15 and the background presence of Passivhaus technical expertise throughout the construction. This built confidence in the client group and for the contractor team. It did ensure problems were addressed quickly and that upskilling happened rapidly.
2. The activity of MVHR commissioning needs to be separated from the installers – this is a key decision and should always be followed as best practice. There were numerous issues discovered at the commissioning – missing connections between valves and ducts, even cover caps left in place blocking air movement. The MVHR contributes so much to the energy performance and to the health of occupiers that it should command extra attention, not less.
3. Holding a ‘handover day’ at the home for every occupant. This was both general and Passivhaus specific. Passivhaus related matters included operation of windows/doors, summer cooling behaviour, how the ventilation works and is controlled and maintained, anticipated bills and heating arrangements, even how to fix onto the walls without affecting airtightness. This was a very positive experience for everyone and created a sense of excitement and included a bottle of prosecco for the occupiers along with their house keys! For a successful and engaged transfer to the occupants this is important. Alongside this Passivhaus Guides were provided for both the occupants and the Housing Association. Using straightforward non-technical language, not too long, but giving all the necessary information around the Passivhaus aspects. These covered the same range of subjects as the handover and only needs to be a dozen or so pages long.
4. After six months of occupation, WHHA collated all the issues which had arisen and sent out a four-page summary letter to ALL the occupants. The delivery team contributed to that process. The matters addressed included the need to add a heater in in the lounge of the two larger 3-bed units (this was a low-cost solution). Someone was living at 24 degrees and needed a reminder that this would cost more, some needed doors readjusted, there was misunderstanding on MVHR functioning as heating – so an occupant setting it too high! There was a fault on the hot water cylinders, this was sorted by the manufacturer, at their cost. It was interesting to see that some occupants had no queries at all while others were much more questioning, one example being asking why ice was forming on the external face of the glazing. This exercise mopped up all those initial niggles that will happen on any new building scheme and was a helpful and very transparent process.
5. Health improvement reports from residents filtered through after about six months too, to the amazement of WHHA. A 9-year-old resident no longer needs inhalers for his asthma morning or evening. He is on less than half the steroids he used to be on. His hay fever is also much improved. We are not surprised to hear these experiences – we do hear many of these stories from occupiers of Passivhaus homes – interestingly this story was very specific on the reduction in medication needed.

We will still need to review again after a year or two and only at that point we will know the level of energy performance we have delivered. It should be at or near the PHPP predictions, we can only verify once the occupant’s bills provide the evidence! The experience so far has been one of pride for both the housing association and the residents. This means that we can hope that it will be repeated on future WHHA housing schemes and become the standard they expect, not the exception.