Sustainability Report

With the extensive use of sustainably sourced and reclaimed timber, natural clay finishes, and preassembled wood panels, Downland Barns most likely achieves a significantly lower embodied carbon footprint compared to conventional construction. However, the embodied carbon of the home has not been formally quantified.

Downland Barns provides an example of a contemporary, low-carbon home that combines advanced technology, renewable energy, and high-quality construction to achieve exceptional energy performance.

Energy performance

• EPC rating: A (score 101)
• Carbon emissions: -1.4 tonnes/year (carbon negative)
• Primary energy use: -17 kWh/m²/year — the home produces more renewable energy than it consumes
• Estimated annual energy cost: £1,637 (covering heating, lighting, and hot water)

Renewable and low-carbon technology

• Viessmann Vitocal 200-A Air Source Heat Pump with underfloor heating and radiators
• A west-facing 15 kWp photovoltaic array with a 45-degree tilt, ensuring clean and sustainable energy generation
• HETAS-approved biomass heating — wood-burning room heaters provide secondary, carbon-neutral heating

Exceptional fabric efficiency

• Insulation: walls (0.19 W/m²K), roof (0.12 W/m²K), and floor (0.20 W/m²K) – all outperform building regulation requirements
• Glazing: high-performance low-E (soft coat) glazing with U-values around 0.78 W/m²K
• Air tightness: tested at 2.3 m³/h.m² @ 50 Pa, reducing heat loss and energy demand

Comfort and indoor climate

• Mechanical Ventilation with Heat Recovery (MVHR): 86 percent efficiency, maintaining fresh air while recycling heat
• Summertime comfort: overheating risk rated as “Not significant”
• Low-energy lighting: 80 percent of fixed lighting uses energy-efficient fittings

Environmental impact

The average UK household produces 6 tonnes of carbon annually, while Downland Barns achieves a net-negative carbon footprint.

Renewable energy systems reduce reliance on fossil fuels, cutting emissions and operational costs.