H & S' EnerPHit / PassivHaus in Deal

EnerPHit coastal home in Deal, Kent

This detached three-storey home on the coast in Deal has been renovated to EnerPHit standard, with an all-electric specification including ASHP, MVHR and EV charging. The clients wanted a solar and battery system that would support their EnerPHit performance targets and keep the long-term running costs of the home as low and predictable as possible.

The brief

As part of the deep retrofit, the homeowners were looking for a high-yield solar PV system with full-home backup and a clear path to future expansion. With the property moving to all-electric heating, hot water, ventilation and transport, the system needed to:

• Maximise generation from the available roof space

• Provide whole-home backup in the event of a power cut

• Integrate DC-coupled EV charging and V2H capability

• Allow additional battery capacity to be added later, without major disruption

System design

To make the most of the roof area, an on-roof array was selected rather than an in-roof system, prioritising output over the small aesthetic gain of in-roof. The final design uses 33 Aiko 475 W panels, giving a total array size of 15.675 kWp. The panels are split across three elevations – 12 on the East roof, 9 on the South and 12 on the West – to create a broader, more linear generation curve through the day, well matched to an occupied home with background loads.

At the heart of the system is a 25 kW Sigenergy inverter, paired with a 9.04 kWh SigenStor battery. Although the initial battery capacity is modest relative to the PV size, the SigenStor platform makes storage expansion straightforward, with additional modules able to be added in around 20 minutes when the client is ready to increase capacity.

EV integration and backup

The project also includes a 25 kW Sigenergy DC-to-DC EV charger, installed alongside the inverter and battery as a single, discreet external stack on the plant side of the building. The services are located next to a GRP kiosk housing the Gateway, close to the service head and meter, keeping all of the main energy infrastructure together in one area.

The system is configured for whole-home “full fat” backup. In the event of a grid outage, the 9.04 kWh SigenStor battery takes over immediately to keep the property running. Once the EV is plugged in, the bidirectional charger allows the vehicle to act as a large V2H battery, with up to around 110 kWh of additional storage available from the car. This combination of fixed storage and V2H support gives the homeowners a high level of resilience, with enough power and capacity to comfortably run the house through extended power cuts.

Phased installation

The installation was completed in two phases to suit the wider EnerPHit works. In phase one, the roof-mounted PV array was installed as a “first fix”, allowing the roofing and façade works to progress around a completed solar install. Around four months later, once the building fabric and services were ready, phase two saw the Sigenergy inverter, SigenStor battery, Gateway and DC-to-DC EV charger installed and commissioned as a single, integrated system.

This approach kept the project moving smoothly on site, while ensuring the final system is fully coordinated with the fabric-first EnerPHit retrofit, ready to support a highly efficient, all-electric home from day one of occupation.

Ready to explore something similar for your own home or EnerPHit / Passivhaus project? Get in touch to talk through design options, budgets and what’s realistically possible for your property.