Eco-refurbishing a large Victorian semi-detached home

In North Oxford, a large family home has been transformed through an eco-retrofit, reducing carbon emissions and making the home far more energy-efficient. This was all part of the homeowners’ commitment to sustainability and creating a more comfortable living space.

Cosy Homes Oxfordshire took on the project, retrofitting the Victorian semi-detached house by replacing the old fossil fuel boiler with an air source heat pump. This upgrade was crucial in improving comfort and cutting down the home’s carbon footprint.

The home was assessed and measured and provided with a Whole House Plan before proceeding with any work.

About the home

Built in the 1880s, this house also had a two-storey extension added in 2013. It’s a well-maintained, multi-storey property that has served as a family home for years. The homeowners loved the space it offered, especially as it allowed them to host friends and family frequently.

Caption: Retrofit Coordinator Mark Saunders explained that the ceilings were removed to install the underfloor heating ducting, which is fitted into trays mounted between the joists of the floor above.

Why retrofit?

Climate concerns

The homeowners were deeply motivated by the need to reduce their home’s carbon emissions. Having already taken steps in other areas of their lives to address the climate emergency, they felt it was time to tackle their home’s energy inefficiency. They wanted to show how even large, older homes could become energy efficient and support the local low-carbon building industry in the process.

"Houses like this are incredibly energy inefficient, so from the start, we knew we'd have to improve it significantly if we bought it." Meg — *“Houses like this are incredibly energy inefficient, so from the start, we knew we’d have to improve it significantly if we bought it.”* Meg

Comfort issues

The home had always been cold in winter, with noticeable draughts and cold spots throughout. This made the house uncomfortable and meant wasting energy on heating that simply escaped through the walls, floors, and windows.

“You could really feel the cold spots and draughts, especially around the single-glazed windows and under doors. It took a lot of energy to keep the house warm.”

Meg, Cosy Homes Oxfordshire client

What we did

To begin, Cosy Homes Oxfordshire developed a Whole House Plan, identifying the best upgrades and the order in which they should be tackled. The key measures included:

Installing new double-glazed sash windows
Adding internal wall insulation with wood fibre
Installing an air source heat pump
Underfloor insulation and heating
Re-roofing with loft insulation
Setting up centralised mechanical extract ventilation

“We needed to make it more energy efficient to feel comfortable living here for many years.”

The biggest initial step was applying internal wall insulation to three sides of the house. This required removing the plaster, adding wood fibre insulation, and re-plastering. Wood fibre was chosen because it’s breathable, renewable, and ideal for older properties with solid walls. It not only insulates but helps maintain a healthy airflow.

"A ground source heat pump would’ve required too much work in the garden, so an air source heat pump was the obvious choice. We were excited to find it was compatible with a house of this size." — “A ground source heat pump would’ve required too much work in the garden, so an air source heat pump was the obvious choice. We were excited to find it was compatible with a house of this size.”

Once the insulation was in place, the loft and floors were insulated, ensuring the entire house was snug. This allowed the complete removal of the gas heating system, which was replaced by an air source heat pump, installed in the cellar and connected to underfloor heating throughout the house.

To maintain good air quality and protect the building’s structure, a mechanical ventilation system was installed, ensuring effective air circulation across all levels of the home.

Sustainable Materials

The homeowners were eager to use sustainable and natural materials wherever possible. They chose materials such as wood fibre insulation, which is made from wood processing offcuts, and cotton insulation made from recycled denim jeans, which offers excellent thermal and sound insulation.

In humid areas like the basement and bathrooms, cork insulation was used. This material, harvested from tree bark, regenerates over time and is ideal for moisture-rich environments. Beneath the cellar floor, recycled glass formed a honeycomb structure to insulate and keep moisture out.

"One of the biggest challenges was accepting that some waste is inevitable with any building project. We wanted to minimise the impact of emissions from new materials wherever possible." Meg, Cosy Homes Oxfordshire client — “One of the biggest challenges was accepting that some waste is inevitable with any building project. We wanted to minimise the impact of emissions from new materials wherever possible.” Meg

Samples: Wood fibre insulation (top left), Cork insulation (bottom left), Recycled Glass (top right), Calsitherm (bottom right)

Why Cosy Homes Oxfordshire?

The homeowners were pleased with the expertise and commitment of the Cosy Homes Oxfordshire team. They appreciated the personal touch and the bespoke approach that their Retrofit Coordinator, Geordie Stewart, brought to the project. His experience and understanding of older homes were essential in managing the complexity of the retrofit.

Their Retrofit Coordinator, Geordie Stewart, provided essential expertise and experience in a bespoke approach enabling change to happen.

“We really appreciated Geordie’s technical expertise and experience. His knowledge of different properties helped us tackle issues we didn’t fully understand, and his personal approach made the process smoother.“

Retrofit Scheme Manager, Geordie Stewart

Geordie was recognised as Retrofit Coordinator of the year for his work with Cosy Homes at The Retrofit Academy Awards 2022

The impact

By following the Whole House Plan, the retrofit significantly reduced the home’s energy use, cutting carbon emissions and making the house warmer and more comfortable year-round. The estimated savings in energy and carbon emissions, calculated at the time of the plan, show a clear reduction in the home’s environmental impact.

“With our busy jobs and young family, we had no expertise or time for a project this ambitious. The support we received made all the difference – we wouldn’t have had the courage to do it on our own.”

Ready to make your home more comfortable?

If you’re looking to refurbish your home and live in Oxfordshire, our team of experts can help you explore your options. With our Free Plan Builder advice service, you can start building an energy efficiency plan for your home in just a few minutes.

Enter your postcode, and you’ll see details about your home’s current energy efficiency based on existing data. Then, set your budget and priorities, and the Plan Builder will create a draft retrofit plan – ready for you to adjust as needed. Let’s make your home cosy for all seasons!

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