Most energy efficient row of homes in UK relies on Fronius

10/01/2025 / Nottinghamshire, UK

When Dr Chris Parsons found himself in charge of the family farm where he grew up, he envisioned transforming the land into a model of sustainability by developing both affordable and environmentally friendly dwellings. Collaborating with Technical Design Consultant Dr Jerry Harrall, known for his expertise in fossil fuel-free designs, Chris embarked on creating nine energy-efficient homes on the farm's land. This innovative project stands as a testament to how smart design, combined with cutting-edge technology like Fronius inverters, can pave the way for a sustainable future.

Arial and side view of an example of the homes that feature in the Howgate Close project

Local homes for local people

The homes were built to rent out to local people, with the shortage of suitable and affordable accommodation in the local area in mind. The build cost of each unit is comparable to a conventionally constructed house, but the scheme's energy and cost savings are far superior. Each dwelling is a masterpiece of thermal efficiency, constructed as a high thermal mass concrete box.

These homes feature triple-glazed, south-facing windows that serve as natural heat gatherers, enclosed in a continuous, super-insulated jacket of polystyrene. This innovative design includes a unique foundation system where the building floats on a concrete slab atop a polystyrene base, effectively turning the entire building into an energy storage system and a 30W heat exchange fan efficiently supplements fresh air.

The design enables a comfortable internal temperature of 21°C to 23°C that is maintained the year round, whilst reaching only 26°C during a heatwave. The interior is equally impressive, with ceramic tile flooring and rendered walls and ceilings, with the homes seamlessly blending into their natural surroundings through bunding.

View of home at the Howgate Close project

Harnessing solar energy and cost savings

Harnessing the power of the sun is central to the sustainability of these homes, with 60kW of solar PV installed. Altogether, 136 roof-mounted 440Watt RES panels and nine Fronius Primo single-phase inverters, installed by Cambridge Solar, provide clean electricity for residents. The Fronius inverters efficiently convert DC electricity from the solar panels into AC power, which each of the nine households uses for their fully electric homes. The scheme uses both Primo 6.0 and Primo 4.6 inverters.

The project uses only the most reliable products throughout and Fronius Primo SnapINverters were specified due to their consistent high performance and also low failure rates. “Howgate is a low energy and low maintenance project, selecting an inverter that reflected those performance characteristics led us to Fronius," states Dr Jerry Harrall.

» Howgate is a low energy and low maintenance project, selecting an inverter that reflected those performance characteristics led us to Fronius «

Dr Jerry Harrall, Technical Design Consultant

Image of Fronius inverter in the Howgate Close project

Powered by Primo's

All nine Fronius Primo inverters are mounted on the external walls of the houses, which is another reason Fronius inverters were well suited for this project, as they can withstand extreme temperatures from -40°C to +55°C and are IP65 rated making them well protected in bad weather. Fronius runs rigorous robustness and endurance tests on their entire range of products that go far beyond standards, and testing conditions are up to ten times more severe than those found in nature.

This build and setup not only minimises energy consumption but also reduces costs, with an impressive average household running cost of less than 45 pence per day. These financial savings are extraordinary.

For residents like Andrew Wells - who was the first to move into a two-bedroom house at Howgate Close - this development is transformative. A farmhand, Andrew was previously unable to afford local housing, with rental costs sitting above £800 plus bills. The affordable £830 monthly cost of these two-bedroom homes, inclusive of bills, is a welcome change.

Furthermore, the project generates an average of 48,000 kWh of renewable electricity per year, with excess electricity sold back to the grid, creating an additional source of income, which is offset against the resident’s bills. This amount of electricity produced from renewables saves approximately 10 metric tonnes of CO2 annually. This is the equivalent of driving more than 40,128 km in a car.

Award-winning and standard-setting project

The homes’ energy performance is remarkable, boasting EPC ratings of A - far surpassing the national average of D in England and Wales. The project has also been awarded a SAP rating of 143A. As a result, Howgate Close has earned recognition through eleven national and three international awards, and has been featured in peer-reviewed science papers and conference proceedings. Currently, Howgate Close is the most energy-efficient row of small houses in the UK.

By championing innovation and sustainability, Dr Chris Parsons and his team have set a new standard for energy-efficient living. Howgate Close is more than just a collection of homes; it is a beacon of environmental responsibility, demonstrating how forward-thinking design can lead to both economic savings and a healthier planet.

Chris takes his responsibilities as an investor extremely seriously, “When looking at future investments, I always ask myself what does it cost in the pocket, what does it cost to the tenants and what does it cost to the earth.”

For investors looking for their next eco-friendly development, incorporating renewable energy, the success of Howgate Close serves as an inspiring model to follow.

» When looking at future investments, I always ask myself what does it cost in the pocket, what does it cost to the tenants and what does it cost to the earth. «

Dr Chris Parsons, Project Owner

About the system:

60kWp PV system with Fronius Primo 6.0 and 4.6 SnapINverters
Produces an annual yield of 48,000kWh with excess energy being sold back to the grid for additional income
CO2 savings of approximately 10 metric tonnes per year - equivalent to driving 24,934 miles in a car
EPC rating of A
SAP rating of 143A
Winner of 11 national and 3 international awards

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