A 1930s detached home in Cambridge has been transformed into a fully-electric, high-performance dwelling with a retrofit budget of around £100 k (incl. VAT). Between November 2024 and May 2025 the house underwent major upgrades to reduce its carbon footprint, enhance comfort and future-proof for renewables.

Key features include:

• External wall insulation (100 mm BAUMIT EPS + retained internal insulation) to achieve a U-value of approx. 0.15 W/m²K (0.30 W/m²K where internal insulation is missing).

• New timber-framed, triple-glazed windows in the conservatory to Passivhaus standard; external “Maanta” blinds to control overheating.

• A 5 kW Vaillant Arotherm Plus air-source heat pump paired with fan-convector radiators and three single-room MVHR units (kitchen, bathroom, living room).

• A new electrical switchboard ready for EV charging and photovoltaics, meaning the house is now ready to fully embrace renewables.

• Landscaping and biodiversity improvements: rainwater butts, a pond, bird-friendly hedges and a raised vegetable bed contribute to the outdoor environment.

The result is a home that not only looks bold and bright but performs significantly better – reducing overheating in the summer, improving comfort in the winter and setting a strong example of how retrofit can be effective even without an unlimited budget.